libstdc++
bits/hashtable.h
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1// hashtable.h header -*- C++ -*-
2
3// Copyright (C) 2007-2024 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file bits/hashtable.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{unordered_map, unordered_set}
28 */
29
30#ifndef _HASHTABLE_H
31#define _HASHTABLE_H 1
32
33#ifdef _GLIBCXX_SYSHDR
34#pragma GCC system_header
35#endif
36
39#include <bits/stl_algobase.h> // fill_n, is_permutation
40#include <bits/stl_function.h> // __has_is_transparent_t
41#if __cplusplus > 201402L
42# include <bits/node_handle.h>
43#endif
44
45#pragma GCC diagnostic push
46#pragma GCC diagnostic ignored "-Wc++11-extensions"
47
48namespace std _GLIBCXX_VISIBILITY(default)
49{
50_GLIBCXX_BEGIN_NAMESPACE_VERSION
51/// @cond undocumented
52
53 template<typename _Tp, typename _Hash>
54 using __cache_default
55 = __not_<__and_<// Do not cache for fast hasher.
56 __is_fast_hash<_Hash>,
57 // Mandatory for the rehash process.
58 __is_nothrow_invocable<const _Hash&, const _Tp&>>>;
59
60 // Helper to conditionally delete the default constructor.
61 // The _Hash_node_base type is used to distinguish this specialization
62 // from any other potentially-overlapping subobjects of the hashtable.
63 template<typename _Equal, typename _Hash, typename _Allocator>
64 using _Hashtable_enable_default_ctor
65 = _Enable_default_constructor<__and_<is_default_constructible<_Equal>,
66 is_default_constructible<_Hash>,
67 is_default_constructible<_Allocator>>{},
68 __detail::_Hash_node_base>;
69
70 /**
71 * Primary class template _Hashtable.
72 *
73 * @ingroup hashtable-detail
74 *
75 * @tparam _Value CopyConstructible type.
76 *
77 * @tparam _Key CopyConstructible type.
78 *
79 * @tparam _Alloc An allocator type
80 * ([lib.allocator.requirements]) whose _Alloc::value_type is
81 * _Value. As a conforming extension, we allow for
82 * _Alloc::value_type != _Value.
83 *
84 * @tparam _ExtractKey Function object that takes an object of type
85 * _Value and returns a value of type _Key.
86 *
87 * @tparam _Equal Function object that takes two objects of type k
88 * and returns a bool-like value that is true if the two objects
89 * are considered equal.
90 *
91 * @tparam _Hash The hash function. A unary function object with
92 * argument type _Key and result type size_t. Return values should
93 * be distributed over the entire range [0, numeric_limits<size_t>:::max()].
94 *
95 * @tparam _RangeHash The range-hashing function (in the terminology of
96 * Tavori and Dreizin). A binary function object whose argument
97 * types and result type are all size_t. Given arguments r and N,
98 * the return value is in the range [0, N).
99 *
100 * @tparam _Unused Not used.
101 *
102 * @tparam _RehashPolicy Policy class with three members, all of
103 * which govern the bucket count. _M_next_bkt(n) returns a bucket
104 * count no smaller than n. _M_bkt_for_elements(n) returns a
105 * bucket count appropriate for an element count of n.
106 * _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
107 * current bucket count is n_bkt and the current element count is
108 * n_elt, we need to increase the bucket count for n_ins insertions.
109 * If so, returns make_pair(true, n), where n is the new bucket count. If
110 * not, returns make_pair(false, <anything>)
111 *
112 * @tparam _Traits Compile-time class with three boolean
113 * std::integral_constant members: __cache_hash_code, __constant_iterators,
114 * __unique_keys.
115 *
116 * Each _Hashtable data structure has:
117 *
118 * - _Bucket[] _M_buckets
119 * - _Hash_node_base _M_before_begin
120 * - size_type _M_bucket_count
121 * - size_type _M_element_count
122 *
123 * with _Bucket being _Hash_node_base* and _Hash_node containing:
124 *
125 * - _Hash_node* _M_next
126 * - Tp _M_value
127 * - size_t _M_hash_code if cache_hash_code is true
128 *
129 * In terms of Standard containers the hashtable is like the aggregation of:
130 *
131 * - std::forward_list<_Node> containing the elements
132 * - std::vector<std::forward_list<_Node>::iterator> representing the buckets
133 *
134 * The non-empty buckets contain the node before the first node in the
135 * bucket. This design makes it possible to implement something like a
136 * std::forward_list::insert_after on container insertion and
137 * std::forward_list::erase_after on container erase
138 * calls. _M_before_begin is equivalent to
139 * std::forward_list::before_begin. Empty buckets contain
140 * nullptr. Note that one of the non-empty buckets contains
141 * &_M_before_begin which is not a dereferenceable node so the
142 * node pointer in a bucket shall never be dereferenced, only its
143 * next node can be.
144 *
145 * Walking through a bucket's nodes requires a check on the hash code to
146 * see if each node is still in the bucket. Such a design assumes a
147 * quite efficient hash functor and is one of the reasons it is
148 * highly advisable to set __cache_hash_code to true.
149 *
150 * The container iterators are simply built from nodes. This way
151 * incrementing the iterator is perfectly efficient independent of
152 * how many empty buckets there are in the container.
153 *
154 * On insert we compute the element's hash code and use it to find the
155 * bucket index. If the element must be inserted in an empty bucket
156 * we add it at the beginning of the singly linked list and make the
157 * bucket point to _M_before_begin. The bucket that used to point to
158 * _M_before_begin, if any, is updated to point to its new before
159 * begin node.
160 *
161 * Note that all equivalent values, if any, are next to each other, if
162 * we find a non-equivalent value after an equivalent one it means that
163 * we won't find any new equivalent value.
164 *
165 * On erase, the simple iterator design requires using the hash
166 * functor to get the index of the bucket to update. For this
167 * reason, when __cache_hash_code is set to false the hash functor must
168 * not throw and this is enforced by a static assertion.
169 *
170 * Functionality is implemented by decomposition into base classes,
171 * where the derived _Hashtable class is used in _Map_base and
172 * _Rehash_base base classes to access the
173 * "this" pointer. _Hashtable_base is used in the base classes as a
174 * non-recursive, fully-completed-type so that detailed nested type
175 * information, such as iterator type and node type, can be
176 * used. This is similar to the "Curiously Recurring Template
177 * Pattern" (CRTP) technique, but uses a reconstructed, not
178 * explicitly passed, template pattern.
179 *
180 * Base class templates are:
181 * - __detail::_Hashtable_base
182 * - __detail::_Map_base
183 * - __detail::_Rehash_base
184 */
185 template<typename _Key, typename _Value, typename _Alloc,
186 typename _ExtractKey, typename _Equal,
187 typename _Hash, typename _RangeHash, typename _Unused,
188 typename _RehashPolicy, typename _Traits>
189 class _Hashtable
190 : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
191 _Hash, _RangeHash, _Unused, _Traits>,
192 public __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
193 _Hash, _RangeHash, _Unused,
194 _RehashPolicy, _Traits>,
195 public __detail::_Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
196 _Hash, _RangeHash, _Unused,
197 _RehashPolicy, _Traits>,
198 private __detail::_Hashtable_alloc<
199 __alloc_rebind<_Alloc,
200 __detail::_Hash_node<_Value,
201 _Traits::__hash_cached::value>>>,
202 private _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>
203 {
204 static_assert(is_same<typename remove_cv<_Value>::type, _Value>::value,
205 "unordered container must have a non-const, non-volatile value_type");
206#if __cplusplus > 201703L || defined __STRICT_ANSI__
207 static_assert(is_same<typename _Alloc::value_type, _Value>{},
208 "unordered container must have the same value_type as its allocator");
209#endif
210 static_assert(is_copy_constructible<_Hash>::value,
211 "hash function must be copy constructible");
212
213 using __traits_type = _Traits;
214 using __hash_cached = typename __traits_type::__hash_cached;
215 using __constant_iterators = typename __traits_type::__constant_iterators;
216 using __node_type = __detail::_Hash_node<_Value, __hash_cached::value>;
217 using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
218
219 using __hashtable_alloc = __detail::_Hashtable_alloc<__node_alloc_type>;
220
221 using __node_value_type =
222 __detail::_Hash_node_value<_Value, __hash_cached::value>;
223 using __node_ptr = typename __hashtable_alloc::__node_ptr;
224 using __value_alloc_traits =
225 typename __hashtable_alloc::__value_alloc_traits;
226 using __node_alloc_traits =
227 typename __hashtable_alloc::__node_alloc_traits;
228 using __node_base = typename __hashtable_alloc::__node_base;
229 using __node_base_ptr = typename __hashtable_alloc::__node_base_ptr;
230 using __buckets_ptr = typename __hashtable_alloc::__buckets_ptr;
231
232 using __enable_default_ctor
233 = _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>;
234 using __rehash_guard_t
235 = __detail::_RehashStateGuard<_RehashPolicy>;
236
237 public:
238 typedef _Key key_type;
239 typedef _Value value_type;
240 typedef _Alloc allocator_type;
241 typedef _Equal key_equal;
242
243 // mapped_type, if present, comes from _Map_base.
244 // hasher, if present, comes from _Hash_code_base/_Hashtable_base.
245 typedef typename __value_alloc_traits::pointer pointer;
246 typedef typename __value_alloc_traits::const_pointer const_pointer;
247 typedef value_type& reference;
248 typedef const value_type& const_reference;
249
250 using iterator
251 = __detail::_Node_iterator<_Value, __constant_iterators::value,
252 __hash_cached::value>;
253
254 using const_iterator
255 = __detail::_Node_const_iterator<_Value, __constant_iterators::value,
256 __hash_cached::value>;
257
258 using local_iterator = __detail::_Local_iterator<key_type, _Value,
259 _ExtractKey, _Hash, _RangeHash, _Unused,
260 __constant_iterators::value,
261 __hash_cached::value>;
262
263 using const_local_iterator = __detail::_Local_const_iterator<
264 key_type, _Value,
265 _ExtractKey, _Hash, _RangeHash, _Unused,
266 __constant_iterators::value, __hash_cached::value>;
267
268 private:
269 using __rehash_type = _RehashPolicy;
270
271 using __unique_keys = typename __traits_type::__unique_keys;
272
273 using __hashtable_base = __detail::
274 _Hashtable_base<_Key, _Value, _ExtractKey,
275 _Equal, _Hash, _RangeHash, _Unused, _Traits>;
276
277 using __hash_code_base = typename __hashtable_base::__hash_code_base;
278 using __hash_code = typename __hashtable_base::__hash_code;
279 using __ireturn_type = __conditional_t<__unique_keys::value,
281 iterator>;
282
283 using __map_base = __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey,
284 _Equal, _Hash, _RangeHash, _Unused,
285 _RehashPolicy, _Traits>;
286
287 using __rehash_base = __detail::_Rehash_base<_Key, _Value, _Alloc,
288 _ExtractKey, _Equal,
289 _Hash, _RangeHash, _Unused,
290 _RehashPolicy, _Traits>;
291
292 using __node_builder_t = __detail::_NodeBuilder<_ExtractKey>;
293
294 // Simple RAII type for managing a node containing an element
295 struct _Scoped_node
296 {
297 // Take ownership of a node with a constructed element.
298 _Scoped_node(__node_ptr __n, __hashtable_alloc* __h)
299 : _M_h(__h), _M_node(__n) { }
300
301 // Allocate a node and construct an element within it.
302 template<typename... _Args>
303 _Scoped_node(__hashtable_alloc* __h, _Args&&... __args)
304 : _M_h(__h),
305 _M_node(__h->_M_allocate_node(std::forward<_Args>(__args)...))
306 { }
307
308 // Destroy element and deallocate node.
309 ~_Scoped_node() { if (_M_node) _M_h->_M_deallocate_node(_M_node); };
310
311 _Scoped_node(const _Scoped_node&) = delete;
312 _Scoped_node& operator=(const _Scoped_node&) = delete;
313
314 __hashtable_alloc* _M_h;
315 __node_ptr _M_node;
316 };
317
318 // Compile-time diagnostics.
319
320 // _Hash_code_base has everything protected, so use this derived type to
321 // access it.
322 struct __hash_code_base_access : __hash_code_base
323 { using __hash_code_base::_M_bucket_index; };
324
325 // To get bucket index we need _RangeHash to be non-throwing.
326 static_assert(is_nothrow_default_constructible<_RangeHash>::value,
327 "Functor used to map hash code to bucket index"
328 " must be nothrow default constructible");
329 static_assert(noexcept(
330 std::declval<const _RangeHash&>()((std::size_t)0, (std::size_t)0)),
331 "Functor used to map hash code to bucket index must be"
332 " noexcept");
333
334 // To compute bucket index we also need _ExtractKey to be non-throwing.
335 static_assert(is_nothrow_default_constructible<_ExtractKey>::value,
336 "_ExtractKey must be nothrow default constructible");
337 static_assert(noexcept(
339 "_ExtractKey functor must be noexcept invocable");
340
341 template<typename _Keya, typename _Valuea, typename _Alloca,
342 typename _ExtractKeya, typename _Equala,
343 typename _Hasha, typename _RangeHasha, typename _Unuseda,
344 typename _RehashPolicya, typename _Traitsa,
345 bool _Unique_keysa>
346 friend struct __detail::_Map_base;
347
348 public:
349 using size_type = typename __hashtable_base::size_type;
350 using difference_type = typename __hashtable_base::difference_type;
351
352#if __cplusplus > 201402L
353 using node_type = _Node_handle<_Key, _Value, __node_alloc_type>;
354 using insert_return_type = _Node_insert_return<iterator, node_type>;
355#endif
356
357 private:
358 __buckets_ptr _M_buckets = &_M_single_bucket;
359 size_type _M_bucket_count = 1;
360 __node_base _M_before_begin;
361 size_type _M_element_count = 0;
362 _RehashPolicy _M_rehash_policy;
363
364 // A single bucket used when only need for 1 bucket. Especially
365 // interesting in move semantic to leave hashtable with only 1 bucket
366 // which is not allocated so that we can have those operations noexcept
367 // qualified.
368 // Note that we can't leave hashtable with 0 bucket without adding
369 // numerous checks in the code to avoid 0 modulus.
370 __node_base_ptr _M_single_bucket = nullptr;
371
372 void
373 _M_update_bbegin()
374 {
375 if (auto __begin = _M_begin())
376 _M_buckets[_M_bucket_index(*__begin)] = &_M_before_begin;
377 }
378
379 void
380 _M_update_bbegin(__node_ptr __n)
381 {
382 _M_before_begin._M_nxt = __n;
383 _M_update_bbegin();
384 }
385
386 bool
387 _M_uses_single_bucket(__buckets_ptr __bkts) const
388 { return __builtin_expect(__bkts == &_M_single_bucket, false); }
389
390 bool
391 _M_uses_single_bucket() const
392 { return _M_uses_single_bucket(_M_buckets); }
393
394 static constexpr size_t
395 __small_size_threshold() noexcept
396 {
397 return
398 __detail::_Hashtable_hash_traits<_Hash>::__small_size_threshold();
399 }
400
401 __hashtable_alloc&
402 _M_base_alloc() { return *this; }
403
404 __buckets_ptr
405 _M_allocate_buckets(size_type __bkt_count)
406 {
407 if (__builtin_expect(__bkt_count == 1, false))
408 {
409 _M_single_bucket = nullptr;
410 return &_M_single_bucket;
411 }
412
413 return __hashtable_alloc::_M_allocate_buckets(__bkt_count);
414 }
415
416 void
417 _M_deallocate_buckets(__buckets_ptr __bkts, size_type __bkt_count)
418 {
419 if (_M_uses_single_bucket(__bkts))
420 return;
421
422 __hashtable_alloc::_M_deallocate_buckets(__bkts, __bkt_count);
423 }
424
425 void
426 _M_deallocate_buckets()
427 { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
428
429 // Gets bucket begin, deals with the fact that non-empty buckets contain
430 // their before begin node.
431 __node_ptr
432 _M_bucket_begin(size_type __bkt) const
433 {
434 __node_base_ptr __n = _M_buckets[__bkt];
435 return __n ? static_cast<__node_ptr>(__n->_M_nxt) : nullptr;
436 }
437
438 __node_ptr
439 _M_begin() const
440 { return static_cast<__node_ptr>(_M_before_begin._M_nxt); }
441
442 // Assign *this using another _Hashtable instance. Whether elements
443 // are copied or moved depends on the _Ht reference.
444 template<typename _Ht>
445 void
446 _M_assign_elements(_Ht&&);
447
448 template<typename _Ht>
449 void
450 _M_assign(_Ht&& __ht)
451 {
452 __detail::_AllocNode<__node_alloc_type> __alloc_node_gen(*this);
453 _M_assign(std::forward<_Ht>(__ht), __alloc_node_gen);
454 }
455
456 template<typename _Ht, typename _NodeGenerator>
457 void
458 _M_assign(_Ht&&, _NodeGenerator&);
459
460 void
461 _M_move_assign(_Hashtable&&, true_type);
462
463 void
464 _M_move_assign(_Hashtable&&, false_type);
465
466 void
467 _M_reset() noexcept;
468
469 _Hashtable(const _Hash& __h, const _Equal& __eq,
470 const allocator_type& __a)
471 : __hashtable_base(__h, __eq),
472 __hashtable_alloc(__node_alloc_type(__a)),
473 __enable_default_ctor(_Enable_default_constructor_tag{})
474 { }
475
476 template<bool _No_realloc = true>
477 static constexpr bool
478 _S_nothrow_move()
479 {
480#if __cplusplus <= 201402L
481 return __and_<__bool_constant<_No_realloc>,
482 is_nothrow_copy_constructible<_Hash>,
483 is_nothrow_copy_constructible<_Equal>>::value;
484#else
485 if constexpr (_No_realloc)
486 if constexpr (is_nothrow_copy_constructible<_Hash>())
487 return is_nothrow_copy_constructible<_Equal>();
488 return false;
489#endif
490 }
491
492 _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
493 true_type /* alloc always equal */)
494 noexcept(_S_nothrow_move());
495
496 _Hashtable(_Hashtable&&, __node_alloc_type&&,
497 false_type /* alloc always equal */);
498
499 template<typename _InputIterator>
500 _Hashtable(_InputIterator __first, _InputIterator __last,
501 size_type __bkt_count_hint,
502 const _Hash&, const _Equal&, const allocator_type&,
503 true_type __uks);
504
505 template<typename _InputIterator>
506 _Hashtable(_InputIterator __first, _InputIterator __last,
507 size_type __bkt_count_hint,
508 const _Hash&, const _Equal&, const allocator_type&,
509 false_type __uks);
510
511 public:
512 // Constructor, destructor, assignment, swap
513 _Hashtable() = default;
514
515 _Hashtable(const _Hashtable&);
516
517 _Hashtable(const _Hashtable&, const allocator_type&);
518
519 explicit
520 _Hashtable(size_type __bkt_count_hint,
521 const _Hash& __hf = _Hash(),
522 const key_equal& __eql = key_equal(),
523 const allocator_type& __a = allocator_type());
524
525 // Use delegating constructors.
526 _Hashtable(_Hashtable&& __ht)
527 noexcept(_S_nothrow_move())
528 : _Hashtable(std::move(__ht), std::move(__ht._M_node_allocator()),
529 true_type{})
530 { }
531
532 _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
533 noexcept(_S_nothrow_move<__node_alloc_traits::_S_always_equal()>())
534 : _Hashtable(std::move(__ht), __node_alloc_type(__a),
535 typename __node_alloc_traits::is_always_equal{})
536 { }
537
538 explicit
539 _Hashtable(const allocator_type& __a)
540 : __hashtable_alloc(__node_alloc_type(__a)),
541 __enable_default_ctor(_Enable_default_constructor_tag{})
542 { }
543
544 template<typename _InputIterator>
545 _Hashtable(_InputIterator __f, _InputIterator __l,
546 size_type __bkt_count_hint = 0,
547 const _Hash& __hf = _Hash(),
548 const key_equal& __eql = key_equal(),
549 const allocator_type& __a = allocator_type())
550 : _Hashtable(__f, __l, __bkt_count_hint, __hf, __eql, __a,
551 __unique_keys{})
552 { }
553
554 _Hashtable(initializer_list<value_type> __l,
555 size_type __bkt_count_hint = 0,
556 const _Hash& __hf = _Hash(),
557 const key_equal& __eql = key_equal(),
558 const allocator_type& __a = allocator_type())
559 : _Hashtable(__l.begin(), __l.end(), __bkt_count_hint,
560 __hf, __eql, __a, __unique_keys{})
561 { }
562
563 _Hashtable&
564 operator=(const _Hashtable& __ht);
565
566 _Hashtable&
567 operator=(_Hashtable&& __ht)
568 noexcept(__node_alloc_traits::_S_nothrow_move()
569 && is_nothrow_move_assignable<_Hash>::value
570 && is_nothrow_move_assignable<_Equal>::value)
571 {
572 constexpr bool __move_storage =
573 __node_alloc_traits::_S_propagate_on_move_assign()
574 || __node_alloc_traits::_S_always_equal();
575 _M_move_assign(std::move(__ht), __bool_constant<__move_storage>());
576 return *this;
577 }
578
579#pragma GCC diagnostic push
580#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
581 _Hashtable&
582 operator=(initializer_list<value_type> __l)
583 {
584 using __reuse_or_alloc_node_gen_t =
585 __detail::_ReuseOrAllocNode<__node_alloc_type>;
586
587 __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
588 _M_before_begin._M_nxt = nullptr;
589 clear();
590
591 // We assume that all elements of __l are likely to be inserted.
592 auto __l_bkt_count = _M_rehash_policy._M_bkt_for_elements(__l.size());
593
594 // Excess buckets might have been intentionally reserved by the user,
595 // so rehash if we need to grow, but don't shrink.
596 if (_M_bucket_count < __l_bkt_count)
597 rehash(__l_bkt_count);
598
599 __hash_code __code;
600 size_type __bkt;
601 for (auto& __e : __l)
602 {
603 const key_type& __k = _ExtractKey{}(__e);
604
605 if constexpr (__unique_keys::value)
606 {
607 if (auto __loc = _M_locate(__k))
608 continue; // Found existing element with equivalent key
609 else
610 {
611 __code = __loc._M_hash_code;
612 __bkt = __loc._M_bucket_index;
613 }
614 }
615 else
616 {
617 __code = this->_M_hash_code(__k);
618 __bkt = _M_bucket_index(__code);
619 }
620
621 _M_insert_unique_node(__bkt, __code, __roan(__e));
622 }
623
624 return *this;
625 }
626#pragma GCC diagnostic pop
627
628 ~_Hashtable() noexcept;
629
630 void
631 swap(_Hashtable&)
632 noexcept(__and_<__is_nothrow_swappable<_Hash>,
633 __is_nothrow_swappable<_Equal>>::value);
634
635 // Basic container operations
636 iterator
637 begin() noexcept
638 { return iterator(_M_begin()); }
639
640 const_iterator
641 begin() const noexcept
642 { return const_iterator(_M_begin()); }
643
644 iterator
645 end() noexcept
646 { return iterator(nullptr); }
647
648 const_iterator
649 end() const noexcept
650 { return const_iterator(nullptr); }
651
652 const_iterator
653 cbegin() const noexcept
654 { return const_iterator(_M_begin()); }
655
656 const_iterator
657 cend() const noexcept
658 { return const_iterator(nullptr); }
659
660 size_type
661 size() const noexcept
662 { return _M_element_count; }
663
664 _GLIBCXX_NODISCARD bool
665 empty() const noexcept
666 { return size() == 0; }
667
668 allocator_type
669 get_allocator() const noexcept
670 { return allocator_type(this->_M_node_allocator()); }
671
672 size_type
673 max_size() const noexcept
674 { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
675
676 // Observers
677 key_equal
678 key_eq() const
679 { return this->_M_eq(); }
680
681 // hash_function, if present, comes from _Hash_code_base.
682
683 // Bucket operations
684 size_type
685 bucket_count() const noexcept
686 { return _M_bucket_count; }
687
688 size_type
689 max_bucket_count() const noexcept
690 { return max_size(); }
691
692 size_type
693 bucket_size(size_type __bkt) const
694 { return std::distance(begin(__bkt), end(__bkt)); }
695
696 size_type
697 bucket(const key_type& __k) const
698 { return _M_bucket_index(this->_M_hash_code(__k)); }
699
700 local_iterator
701 begin(size_type __bkt)
702 {
703 return local_iterator(*this, _M_bucket_begin(__bkt),
704 __bkt, _M_bucket_count);
705 }
706
707 local_iterator
708 end(size_type __bkt)
709 { return local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
710
711 const_local_iterator
712 begin(size_type __bkt) const
713 {
714 return const_local_iterator(*this, _M_bucket_begin(__bkt),
715 __bkt, _M_bucket_count);
716 }
717
718 const_local_iterator
719 end(size_type __bkt) const
720 { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
721
722 // DR 691.
723 const_local_iterator
724 cbegin(size_type __bkt) const
725 {
726 return const_local_iterator(*this, _M_bucket_begin(__bkt),
727 __bkt, _M_bucket_count);
728 }
729
730 const_local_iterator
731 cend(size_type __bkt) const
732 { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
733
734 float
735 load_factor() const noexcept
736 {
737 return static_cast<float>(size()) / static_cast<float>(bucket_count());
738 }
739
740 // max_load_factor, if present, comes from _Rehash_base.
741
742 // Generalization of max_load_factor. Extension, not found in
743 // TR1. Only useful if _RehashPolicy is something other than
744 // the default.
745 const _RehashPolicy&
746 __rehash_policy() const
747 { return _M_rehash_policy; }
748
749 void
750 __rehash_policy(const _RehashPolicy& __pol)
751 { _M_rehash_policy = __pol; }
752
753 // Lookup.
754 iterator
755 find(const key_type& __k);
756
757 const_iterator
758 find(const key_type& __k) const;
759
760 size_type
761 count(const key_type& __k) const;
762
764 equal_range(const key_type& __k);
765
767 equal_range(const key_type& __k) const;
768
769#ifdef __glibcxx_generic_unordered_lookup // C++ >= 20 && HOSTED
770 template<typename _Kt,
771 typename = __has_is_transparent_t<_Hash, _Kt>,
772 typename = __has_is_transparent_t<_Equal, _Kt>>
773 iterator
774 _M_find_tr(const _Kt& __k);
775
776 template<typename _Kt,
777 typename = __has_is_transparent_t<_Hash, _Kt>,
778 typename = __has_is_transparent_t<_Equal, _Kt>>
779 const_iterator
780 _M_find_tr(const _Kt& __k) const;
781
782 template<typename _Kt,
783 typename = __has_is_transparent_t<_Hash, _Kt>,
784 typename = __has_is_transparent_t<_Equal, _Kt>>
785 size_type
786 _M_count_tr(const _Kt& __k) const;
787
788 template<typename _Kt,
789 typename = __has_is_transparent_t<_Hash, _Kt>,
790 typename = __has_is_transparent_t<_Equal, _Kt>>
791 pair<iterator, iterator>
792 _M_equal_range_tr(const _Kt& __k);
793
794 template<typename _Kt,
795 typename = __has_is_transparent_t<_Hash, _Kt>,
796 typename = __has_is_transparent_t<_Equal, _Kt>>
797 pair<const_iterator, const_iterator>
798 _M_equal_range_tr(const _Kt& __k) const;
799#endif // __glibcxx_generic_unordered_lookup
800
801 private:
802 // Bucket index computation helpers.
803 size_type
804 _M_bucket_index(const __node_value_type& __n) const noexcept
805 { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
806
807 size_type
808 _M_bucket_index(__hash_code __c) const
809 { return __hash_code_base::_M_bucket_index(__c, _M_bucket_count); }
810
811 // Find and insert helper functions and types
812
813 // Find the node before the one matching the criteria.
814 __node_base_ptr
815 _M_find_before_node(size_type, const key_type&, __hash_code) const;
816
817 template<typename _Kt>
818 __node_base_ptr
819 _M_find_before_node_tr(size_type, const _Kt&, __hash_code) const;
820
821 // A pointer to a particular node and/or a hash code and bucket index
822 // where such a node would be found in the container.
823 struct __location_type
824 {
825 // True if _M_node() is a valid node pointer.
826 explicit operator bool() const noexcept
827 { return static_cast<bool>(_M_before); }
828
829 // An iterator that refers to the node, or end().
830 explicit operator iterator() const noexcept
831 { return iterator(_M_node()); }
832
833 // A const_iterator that refers to the node, or cend().
834 explicit operator const_iterator() const noexcept
835 { return const_iterator(_M_node()); }
836
837 // A pointer to the node, or null.
838 __node_ptr _M_node() const
839 {
840 if (_M_before)
841 return static_cast<__node_ptr>(_M_before->_M_nxt);
842 return __node_ptr();
843 }
844
845 __node_base_ptr _M_before{}; // Must only be used to get _M_nxt
846 __hash_code _M_hash_code{}; // Only valid if _M_bucket_index != -1
847 size_type _M_bucket_index = size_type(-1);
848 };
849
850 // Adaptive lookup to find key, or which bucket it would be in.
851 // For a container smaller than the small size threshold use a linear
852 // search through the whole container, just testing for equality.
853 // Otherwise, calculate the hash code and bucket index for the key,
854 // and search in that bucket.
855 // The return value will have a pointer to the node _before_ the first
856 // node matching the key, if any such node exists. Returning the node
857 // before the desired one allows the result to be used for erasure.
858 // If no matching element is present, the hash code and bucket for the
859 // key will be set, allowing a new node to be inserted at that location.
860 // (The hash code and bucket might also be set when a node is found.)
861 // The _M_before pointer might point to _M_before_begin, so must not be
862 // cast to __node_ptr, and it must not be used to modify *_M_before
863 // except in non-const member functions, such as erase.
864 __location_type
865 _M_locate(const key_type& __k) const;
866
867 __node_ptr
868 _M_find_node(size_type __bkt, const key_type& __key,
869 __hash_code __c) const
870 {
871 if (__node_base_ptr __before_n = _M_find_before_node(__bkt, __key, __c))
872 return static_cast<__node_ptr>(__before_n->_M_nxt);
873 return nullptr;
874 }
875
876 template<typename _Kt>
877 __node_ptr
878 _M_find_node_tr(size_type __bkt, const _Kt& __key,
879 __hash_code __c) const
880 {
881 if (auto __before_n = _M_find_before_node_tr(__bkt, __key, __c))
882 return static_cast<__node_ptr>(__before_n->_M_nxt);
883 return nullptr;
884 }
885
886 // Insert a node at the beginning of a bucket.
887 void
888 _M_insert_bucket_begin(size_type __bkt, __node_ptr __node)
889 {
890 if (_M_buckets[__bkt])
891 {
892 // Bucket is not empty, we just need to insert the new node
893 // after the bucket before begin.
894 __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
895 _M_buckets[__bkt]->_M_nxt = __node;
896 }
897 else
898 {
899 // The bucket is empty, the new node is inserted at the
900 // beginning of the singly-linked list and the bucket will
901 // contain _M_before_begin pointer.
902 __node->_M_nxt = _M_before_begin._M_nxt;
903 _M_before_begin._M_nxt = __node;
904
905 if (__node->_M_nxt)
906 // We must update former begin bucket that is pointing to
907 // _M_before_begin.
908 _M_buckets[_M_bucket_index(*__node->_M_next())] = __node;
909
910 _M_buckets[__bkt] = &_M_before_begin;
911 }
912 }
913
914 // Remove the bucket first node
915 void
916 _M_remove_bucket_begin(size_type __bkt, __node_ptr __next_n,
917 size_type __next_bkt)
918 {
919 if (!__next_n)
920 _M_buckets[__bkt] = nullptr;
921 else if (__next_bkt != __bkt)
922 {
923 _M_buckets[__next_bkt] = _M_buckets[__bkt];
924 _M_buckets[__bkt] = nullptr;
925 }
926 }
927
928 // Get the node before __n in the bucket __bkt
929 __node_base_ptr
930 _M_get_previous_node(size_type __bkt, __node_ptr __n);
931
932 pair<__node_ptr, __hash_code>
933 _M_compute_hash_code(__node_ptr __hint, const key_type& __k) const;
934
935 // Insert node __n with hash code __code, in bucket __bkt (or another
936 // bucket if rehashing is needed).
937 // Assumes no element with equivalent key is already present.
938 // Takes ownership of __n if insertion succeeds, throws otherwise.
939 // __n_elt is an estimated number of elements we expect to insert,
940 // used as a hint for rehashing when inserting a range.
941 iterator
942 _M_insert_unique_node(size_type __bkt, __hash_code,
943 __node_ptr __n, size_type __n_elt = 1);
944
945 // Insert node __n with key __k and hash code __code.
946 // Takes ownership of __n if insertion succeeds, throws otherwise.
947 iterator
948 _M_insert_multi_node(__node_ptr __hint,
949 __hash_code __code, __node_ptr __n);
950
951 template<typename... _Args>
953 _M_emplace_uniq(_Args&&... __args);
954
955#pragma GCC diagnostic push
956#pragma GCC diagnostic ignored "-Wc++14-extensions" // variable templates
957 template<typename _Arg, typename _DArg = __remove_cvref_t<_Arg>,
958 typename = _ExtractKey>
959 static constexpr bool __is_key_type = false;
960
961 template<typename _Arg>
962 static constexpr bool
963 __is_key_type<_Arg, key_type, __detail::_Identity> = true;
964
965 template<typename _Arg, typename _Arg1, typename _Arg2>
966 static constexpr bool
967 __is_key_type<_Arg, pair<_Arg1, _Arg2>, __detail::_Select1st>
968 = is_same<__remove_cvref_t<_Arg1>, key_type>::value;
969#pragma GCC diagnostic pop
970
971 template<typename... _Args>
972 iterator
973 _M_emplace_multi(const_iterator, _Args&&... __args);
974
975 iterator
976 _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n);
977
978 template<typename _InputIterator>
979 void
980 _M_insert_range_multi(_InputIterator __first, _InputIterator __last);
981
982 public:
983#pragma GCC diagnostic push
984#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
985 // Emplace
986 template<typename... _Args>
987 __ireturn_type
988 emplace(_Args&&... __args)
989 {
990 if constexpr (__unique_keys::value)
991 return _M_emplace_uniq(std::forward<_Args>(__args)...);
992 else
993 return _M_emplace_multi(cend(), std::forward<_Args>(__args)...);
994 }
995
996 template<typename... _Args>
997 iterator
998 emplace_hint(const_iterator __hint, _Args&&... __args)
999 {
1000 if constexpr (__unique_keys::value)
1001 return _M_emplace_uniq(std::forward<_Args>(__args)...).first;
1002 else
1003 return _M_emplace_multi(__hint, std::forward<_Args>(__args)...);
1004 }
1005
1006 // Insert
1007 __ireturn_type
1008 insert(const value_type& __v)
1009 {
1010 if constexpr (__unique_keys::value)
1011 return _M_emplace_uniq(__v);
1012 else
1013 return _M_emplace_multi(cend(), __v);
1014 }
1015
1016 iterator
1017 insert(const_iterator __hint, const value_type& __v)
1018 {
1019 if constexpr (__unique_keys::value)
1020 return _M_emplace_uniq(__v).first;
1021 else
1022 return _M_emplace_multi(__hint, __v);
1023 }
1024
1025 __ireturn_type
1026 insert(value_type&& __v)
1027 {
1028 if constexpr (__unique_keys::value)
1029 return _M_emplace_uniq(std::move(__v));
1030 else
1031 return _M_emplace_multi(cend(), std::move(__v));
1032 }
1033
1034 iterator
1035 insert(const_iterator __hint, value_type&& __v)
1036 {
1037 if constexpr (__unique_keys::value)
1038 return _M_emplace_uniq(std::move(__v)).first;
1039 else
1040 return _M_emplace_multi(__hint, std::move(__v));
1041 }
1042
1043#ifdef __glibcxx_unordered_map_try_emplace // C++ >= 17 && HOSTED
1044 template<typename _KType, typename... _Args>
1046 try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
1047 {
1048 __hash_code __code;
1049 size_type __bkt;
1050 if (auto __loc = _M_locate(__k))
1051 return { iterator(__loc), false };
1052 else
1053 {
1054 __code = __loc._M_hash_code;
1055 __bkt = __loc._M_bucket_index;
1056 }
1057
1058 _Scoped_node __node {
1059 this,
1063 };
1064 auto __it = _M_insert_unique_node(__bkt, __code, __node._M_node);
1065 __node._M_node = nullptr;
1066 return { __it, true };
1067 }
1068#endif
1069
1070 void
1071 insert(initializer_list<value_type> __l)
1072 { this->insert(__l.begin(), __l.end()); }
1073
1074 template<typename _InputIterator>
1075 void
1076 insert(_InputIterator __first, _InputIterator __last)
1077 {
1078 if constexpr (__unique_keys::value)
1079 for (; __first != __last; ++__first)
1080 _M_emplace_uniq(*__first);
1081 else
1082 return _M_insert_range_multi(__first, __last);
1083 }
1084
1085 // This overload is only defined for maps, not sets.
1086 template<typename _Pair,
1087 typename = _Require<__not_<is_same<_Key, _Value>>,
1088 is_constructible<value_type, _Pair&&>>>
1089 __ireturn_type
1090 insert(_Pair&& __v)
1091 {
1092 if constexpr (__unique_keys::value)
1093 return _M_emplace_uniq(std::forward<_Pair>(__v));
1094 else
1095 return _M_emplace_multi(cend(), std::forward<_Pair>(__v));
1096 }
1097
1098 // This overload is only defined for maps, not sets.
1099 template<typename _Pair,
1100 typename = _Require<__not_<is_same<_Key, _Value>>,
1101 is_constructible<value_type, _Pair&&>>>
1102 iterator
1103 insert(const_iterator __hint, _Pair&& __v)
1104 {
1105 if constexpr (__unique_keys::value)
1106 return _M_emplace_uniq(std::forward<_Pair>(__v));
1107 else
1108 return _M_emplace_multi(__hint, std::forward<_Pair>(__v));
1109 }
1110#pragma GCC diagnostic pop
1111
1112 // Erase
1113 iterator
1114 erase(const_iterator);
1115
1116 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1117 // 2059. C++0x ambiguity problem with map::erase
1118 iterator
1119 erase(iterator __it)
1120 { return erase(const_iterator(__it)); }
1121
1122 size_type
1123 erase(const key_type& __k);
1124
1125 iterator
1126 erase(const_iterator, const_iterator);
1127
1128 void
1129 clear() noexcept;
1130
1131 // Set number of buckets keeping it appropriate for container's number
1132 // of elements.
1133 void rehash(size_type __bkt_count);
1134
1135 // DR 1189.
1136 // reserve, if present, comes from _Rehash_base.
1137
1138#if __glibcxx_node_extract // >= C++17 && HOSTED
1139 /// Re-insert an extracted node into a container with unique keys.
1140 insert_return_type
1141 _M_reinsert_node(node_type&& __nh)
1142 {
1143 insert_return_type __ret;
1144 if (__nh.empty())
1145 __ret.position = end();
1146 else
1147 {
1148 __glibcxx_assert(get_allocator() == __nh.get_allocator());
1149
1150 if (auto __loc = _M_locate(__nh._M_key()))
1151 {
1152 __ret.node = std::move(__nh);
1153 __ret.position = iterator(__loc);
1154 __ret.inserted = false;
1155 }
1156 else
1157 {
1158 auto __code = __loc._M_hash_code;
1159 auto __bkt = __loc._M_bucket_index;
1160 __ret.position
1161 = _M_insert_unique_node(__bkt, __code, __nh._M_ptr);
1162 __ret.inserted = true;
1163 __nh.release();
1164 }
1165 }
1166 return __ret;
1167 }
1168
1169 /// Re-insert an extracted node into a container with equivalent keys.
1170 iterator
1171 _M_reinsert_node_multi(const_iterator __hint, node_type&& __nh)
1172 {
1173 if (__nh.empty())
1174 return end();
1175
1176 __glibcxx_assert(get_allocator() == __nh.get_allocator());
1177
1178 const key_type& __k = __nh._M_key();
1179 auto __code = this->_M_hash_code(__k);
1180 auto __ret
1181 = _M_insert_multi_node(__hint._M_cur, __code, __nh._M_ptr);
1182 __nh.release();
1183 return __ret;
1184 }
1185
1186 private:
1187 node_type
1188 _M_extract_node(size_t __bkt, __node_base_ptr __prev_n)
1189 {
1190 __node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
1191 if (__prev_n == _M_buckets[__bkt])
1192 _M_remove_bucket_begin(__bkt, __n->_M_next(),
1193 __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
1194 else if (__n->_M_nxt)
1195 {
1196 size_type __next_bkt = _M_bucket_index(*__n->_M_next());
1197 if (__next_bkt != __bkt)
1198 _M_buckets[__next_bkt] = __prev_n;
1199 }
1200
1201 __prev_n->_M_nxt = __n->_M_nxt;
1202 __n->_M_nxt = nullptr;
1203 --_M_element_count;
1204 return { __n, this->_M_node_allocator() };
1205 }
1206
1207 // Hash code for node __src_n with key __k, using this->hash_function().
1208 // Will use a hash code cached in the node if safe to do so. This is
1209 // for use in _M_merge_multi where the node comes from another container
1210 // with a hash function that might not match this->hash_function().
1211 template<typename _H2>
1212 __hash_code
1213 _M_src_hash_code(const _H2&, const key_type& __k,
1214 const __node_value_type& __src_n) const
1215 {
1216 if constexpr (std::is_same_v<_H2, _Hash>)
1217 if constexpr (std::is_empty_v<_Hash>)
1218 // If the node has a cached hash code, it's OK to use it.
1219 return this->_M_hash_code(__src_n);
1220
1221 return this->_M_hash_code(__k);
1222 }
1223
1224 public:
1225 // Extract a node.
1226 node_type
1227 extract(const_iterator __pos)
1228 {
1229 size_t __bkt = _M_bucket_index(*__pos._M_cur);
1230 return _M_extract_node(__bkt,
1231 _M_get_previous_node(__bkt, __pos._M_cur));
1232 }
1233
1234 /// Extract a node.
1235 node_type
1236 extract(const _Key& __k)
1237 {
1238 node_type __nh;
1239 __hash_code __code = this->_M_hash_code(__k);
1240 std::size_t __bkt = _M_bucket_index(__code);
1241 if (__node_base_ptr __prev_node = _M_find_before_node(__bkt, __k, __code))
1242 __nh = _M_extract_node(__bkt, __prev_node);
1243 return __nh;
1244 }
1245
1246 /// Merge from another container of the same type.
1247 void
1248 _M_merge_unique(_Hashtable& __src)
1249 {
1250 __glibcxx_assert(get_allocator() == __src.get_allocator());
1251
1252 using _PTr = pointer_traits<__node_base_ptr>;
1253
1254 auto __n_elt = __src.size();
1255 size_type __first = 1;
1256 // For a container of identical type we can use its private members,
1257 // __src._M_before_begin, __src._M_bucket_index etc.
1258 auto __prev = _PTr::pointer_to(__src._M_before_begin);
1259 while (__n_elt--)
1260 {
1261 const auto __next = __prev->_M_nxt;
1262 const auto& __node = static_cast<__node_type&>(*__next);
1263 const key_type& __k = _ExtractKey{}(__node._M_v());
1264 const auto __loc = _M_locate(__k);
1265 if (__loc)
1266 {
1267 __prev = __next;
1268 continue;
1269 }
1270
1271 auto __src_bkt = __src._M_bucket_index(__node);
1272 auto __nh = __src._M_extract_node(__src_bkt, __prev);
1273 _M_insert_unique_node(__loc._M_bucket_index, __loc._M_hash_code,
1274 __nh._M_ptr, __first * __n_elt + 1);
1275 __nh.release();
1276 __first = 0;
1277 }
1278 }
1279
1280 /// Merge from a compatible container into one with unique keys.
1281 template<typename _Compatible_Hashtable>
1282 void
1283 _M_merge_unique(_Compatible_Hashtable& __src)
1284 {
1285 static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1286 node_type>, "Node types are compatible");
1287 __glibcxx_assert(get_allocator() == __src.get_allocator());
1288
1289 auto __n_elt = __src.size();
1290 size_type __first = 1;
1291 // For a compatible container we can only use the public API,
1292 // so cbegin(), cend(), hash_function(), and extract(iterator).
1293 for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
1294 {
1295 --__n_elt;
1296 auto __pos = __i++;
1297 const key_type& __k = _ExtractKey{}(*__pos);
1298 const auto __loc = _M_locate(__k);
1299 if (__loc)
1300 continue;
1301
1302 auto __nh = __src.extract(__pos);
1303 _M_insert_unique_node(__loc._M_bucket_index,
1304 __loc._M_hash_code, __nh._M_ptr,
1305 __first * __n_elt + 1);
1306 __nh.release();
1307 __first = 0;
1308 }
1309 }
1310
1311 /// Merge from another container of the same type.
1312 void
1313 _M_merge_multi(_Hashtable& __src)
1314 {
1315 __glibcxx_assert(get_allocator() == __src.get_allocator());
1316
1317 if (__src.size() == 0) [[__unlikely__]]
1318 return;
1319
1320 using _PTr = pointer_traits<__node_base_ptr>;
1321
1322 __node_ptr __hint = nullptr;
1323 this->reserve(size() + __src.size());
1324 // For a container of identical type we can use its private members,
1325 // __src._M_before_begin, __src._M_bucket_index etc.
1326 auto __prev = _PTr::pointer_to(__src._M_before_begin);
1327 do
1328 {
1329 const auto& __node = static_cast<__node_type&>(*__prev->_M_nxt);
1330 const key_type& __k = _ExtractKey{}(__node._M_v());
1331 // Hash code from this->hash_function():
1332 auto __code = _M_src_hash_code(__src.hash_function(), __k, __node);
1333 // Bucket index in __src, using code from __src.hash_function():
1334 size_type __src_bkt = __src._M_bucket_index(__node);
1335 auto __nh = __src._M_extract_node(__src_bkt, __prev);
1336 __hint = _M_insert_multi_node(__hint, __code, __nh._M_ptr)._M_cur;
1337 __nh.release();
1338 }
1339 while (__prev->_M_nxt != nullptr);
1340 }
1341
1342 /// Merge from a compatible container into one with equivalent keys.
1343 template<typename _Compatible_Hashtable>
1344 void
1345 _M_merge_multi(_Compatible_Hashtable& __src)
1346 {
1347 static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1348 node_type>, "Node types are compatible");
1349 __glibcxx_assert(get_allocator() == __src.get_allocator());
1350
1351 __node_ptr __hint = nullptr;
1352 this->reserve(size() + __src.size());
1353 // For a compatible container we can only use the public API,
1354 // so cbegin(), cend(), hash_function(), and extract(iterator).
1355 for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
1356 {
1357 auto __pos = __i++;
1358 const key_type& __k = _ExtractKey{}(*__pos);
1359 __hash_code __code
1360 = _M_src_hash_code(__src.hash_function(), __k, *__pos._M_cur);
1361 auto __nh = __src.extract(__pos);
1362 __hint = _M_insert_multi_node(__hint, __code, __nh._M_ptr)._M_cur;
1363 __nh.release();
1364 }
1365 }
1366#endif // C++17 __glibcxx_node_extract
1367
1368 bool
1369 _M_equal(const _Hashtable& __other) const;
1370
1371 private:
1372 // Helper rehash method used when keys are unique.
1373 void _M_rehash(size_type __bkt_count, true_type __uks);
1374
1375 // Helper rehash method used when keys can be non-unique.
1376 void _M_rehash(size_type __bkt_count, false_type __uks);
1377 };
1378
1379 // Definitions of class template _Hashtable's out-of-line member functions.
1380 template<typename _Key, typename _Value, typename _Alloc,
1381 typename _ExtractKey, typename _Equal,
1382 typename _Hash, typename _RangeHash, typename _Unused,
1383 typename _RehashPolicy, typename _Traits>
1384 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1385 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1386 _Hashtable(size_type __bkt_count_hint,
1387 const _Hash& __h, const _Equal& __eq, const allocator_type& __a)
1388 : _Hashtable(__h, __eq, __a)
1389 {
1390 auto __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count_hint);
1391 if (__bkt_count > _M_bucket_count)
1392 {
1393 _M_buckets = _M_allocate_buckets(__bkt_count);
1394 _M_bucket_count = __bkt_count;
1395 }
1396 }
1397
1398 template<typename _Key, typename _Value, typename _Alloc,
1399 typename _ExtractKey, typename _Equal,
1400 typename _Hash, typename _RangeHash, typename _Unused,
1401 typename _RehashPolicy, typename _Traits>
1402 template<typename _InputIterator>
1403 inline
1404 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1405 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1406 _Hashtable(_InputIterator __f, _InputIterator __l,
1407 size_type __bkt_count_hint,
1408 const _Hash& __h, const _Equal& __eq,
1409 const allocator_type& __a, true_type /* __uks */)
1410 : _Hashtable(__bkt_count_hint, __h, __eq, __a)
1411 { this->insert(__f, __l); }
1412
1413 template<typename _Key, typename _Value, typename _Alloc,
1414 typename _ExtractKey, typename _Equal,
1415 typename _Hash, typename _RangeHash, typename _Unused,
1416 typename _RehashPolicy, typename _Traits>
1417 template<typename _InputIterator>
1418 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1419 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1420 _Hashtable(_InputIterator __f, _InputIterator __l,
1421 size_type __bkt_count_hint,
1422 const _Hash& __h, const _Equal& __eq,
1423 const allocator_type& __a, false_type __uks)
1424 : _Hashtable(__h, __eq, __a)
1425 {
1426 auto __nb_elems = __detail::__distance_fw(__f, __l);
1427 auto __bkt_count =
1428 _M_rehash_policy._M_next_bkt(
1429 std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
1430 __bkt_count_hint));
1431
1432 if (__bkt_count > _M_bucket_count)
1433 {
1434 _M_buckets = _M_allocate_buckets(__bkt_count);
1435 _M_bucket_count = __bkt_count;
1436 }
1437
1438 for (; __f != __l; ++__f)
1439 _M_emplace_multi(cend(), *__f);
1440 }
1441
1442 template<typename _Key, typename _Value, typename _Alloc,
1443 typename _ExtractKey, typename _Equal,
1444 typename _Hash, typename _RangeHash, typename _Unused,
1445 typename _RehashPolicy, typename _Traits>
1446 auto
1447 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1448 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1449 operator=(const _Hashtable& __ht)
1450 -> _Hashtable&
1451 {
1452 if (&__ht == this)
1453 return *this;
1454
1455 if (__node_alloc_traits::_S_propagate_on_copy_assign())
1456 {
1457 auto& __this_alloc = this->_M_node_allocator();
1458 auto& __that_alloc = __ht._M_node_allocator();
1459 if (!__node_alloc_traits::_S_always_equal()
1460 && __this_alloc != __that_alloc)
1461 {
1462 // Replacement allocator cannot free existing storage.
1463 this->_M_deallocate_nodes(_M_begin());
1464 _M_before_begin._M_nxt = nullptr;
1465 _M_deallocate_buckets();
1466 _M_buckets = nullptr;
1467 std::__alloc_on_copy(__this_alloc, __that_alloc);
1468 __hashtable_base::operator=(__ht);
1469 _M_bucket_count = __ht._M_bucket_count;
1470 _M_element_count = __ht._M_element_count;
1471 _M_rehash_policy = __ht._M_rehash_policy;
1472
1473 struct _Guard
1474 {
1475 ~_Guard() { if (_M_ht) _M_ht->_M_reset(); }
1476 _Hashtable* _M_ht;
1477 };
1478 // If _M_assign exits via an exception it will have deallocated
1479 // all memory. This guard will ensure *this is in a usable state.
1480 _Guard __guard{this};
1481 _M_assign(__ht);
1482 __guard._M_ht = nullptr;
1483 return *this;
1484 }
1485 std::__alloc_on_copy(__this_alloc, __that_alloc);
1486 }
1487
1488 // Reuse allocated buckets and nodes.
1489 _M_assign_elements(__ht);
1490 return *this;
1491 }
1492
1493 template<typename _Key, typename _Value, typename _Alloc,
1494 typename _ExtractKey, typename _Equal,
1495 typename _Hash, typename _RangeHash, typename _Unused,
1496 typename _RehashPolicy, typename _Traits>
1497 template<typename _Ht>
1498 void
1499 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1500 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1501 _M_assign_elements(_Ht&& __ht)
1502 {
1503 using __reuse_or_alloc_node_gen_t =
1504 __detail::_ReuseOrAllocNode<__node_alloc_type>;
1505
1506 __buckets_ptr __former_buckets = nullptr;
1507 std::size_t __former_bucket_count = _M_bucket_count;
1508 __rehash_guard_t __rehash_guard(_M_rehash_policy);
1509
1510 if (_M_bucket_count != __ht._M_bucket_count)
1511 {
1512 __former_buckets = _M_buckets;
1513 _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
1514 _M_bucket_count = __ht._M_bucket_count;
1515 }
1516 else
1517 std::fill_n(_M_buckets, _M_bucket_count, nullptr);
1518
1519 __try
1520 {
1521 __hashtable_base::operator=(std::forward<_Ht>(__ht));
1522 _M_element_count = __ht._M_element_count;
1523 _M_rehash_policy = __ht._M_rehash_policy;
1524 __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
1525 _M_before_begin._M_nxt = nullptr;
1526 _M_assign(std::forward<_Ht>(__ht), __roan);
1527 if (__former_buckets)
1528 _M_deallocate_buckets(__former_buckets, __former_bucket_count);
1529 __rehash_guard._M_guarded_obj = nullptr;
1530 }
1531 __catch(...)
1532 {
1533 if (__former_buckets)
1534 {
1535 // Restore previous buckets.
1536 _M_deallocate_buckets();
1537 _M_buckets = __former_buckets;
1538 _M_bucket_count = __former_bucket_count;
1539 }
1540 std::fill_n(_M_buckets, _M_bucket_count, nullptr);
1541 __throw_exception_again;
1542 }
1543 }
1544
1545 template<typename _Key, typename _Value, typename _Alloc,
1546 typename _ExtractKey, typename _Equal,
1547 typename _Hash, typename _RangeHash, typename _Unused,
1548 typename _RehashPolicy, typename _Traits>
1549 template<typename _Ht, typename _NodeGenerator>
1550 void
1551 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1552 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1553 _M_assign(_Ht&& __ht, _NodeGenerator& __node_gen)
1554 {
1555 struct _Guard
1556 {
1557 ~_Guard()
1558 {
1559 if (_M_ht)
1560 {
1561 _M_ht->clear();
1562 if (_M_dealloc_buckets)
1563 _M_ht->_M_deallocate_buckets();
1564 }
1565 }
1566 _Hashtable* _M_ht = nullptr;
1567 bool _M_dealloc_buckets = false;
1568 };
1569 _Guard __guard;
1570
1571 if (!_M_buckets)
1572 {
1573 _M_buckets = _M_allocate_buckets(_M_bucket_count);
1574 __guard._M_dealloc_buckets = true;
1575 }
1576
1577 if (!__ht._M_before_begin._M_nxt)
1578 return;
1579
1580 __guard._M_ht = this;
1581
1582 using _FromVal = __conditional_t<is_lvalue_reference<_Ht>::value,
1583 const value_type&, value_type&&>;
1584
1585 // First deal with the special first node pointed to by
1586 // _M_before_begin.
1587 __node_ptr __ht_n = __ht._M_begin();
1588 __node_ptr __this_n
1589 = __node_gen(static_cast<_FromVal>(__ht_n->_M_v()));
1590 this->_M_copy_code(*__this_n, *__ht_n);
1591 _M_update_bbegin(__this_n);
1592
1593 // Then deal with other nodes.
1594 __node_ptr __prev_n = __this_n;
1595 for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
1596 {
1597 __this_n = __node_gen(static_cast<_FromVal>(__ht_n->_M_v()));
1598 __prev_n->_M_nxt = __this_n;
1599 this->_M_copy_code(*__this_n, *__ht_n);
1600 size_type __bkt = _M_bucket_index(*__this_n);
1601 if (!_M_buckets[__bkt])
1602 _M_buckets[__bkt] = __prev_n;
1603 __prev_n = __this_n;
1604 }
1605 __guard._M_ht = nullptr;
1606 }
1607
1608 template<typename _Key, typename _Value, typename _Alloc,
1609 typename _ExtractKey, typename _Equal,
1610 typename _Hash, typename _RangeHash, typename _Unused,
1611 typename _RehashPolicy, typename _Traits>
1612 void
1613 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1614 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1615 _M_reset() noexcept
1616 {
1617 _M_rehash_policy._M_reset();
1618 _M_bucket_count = 1;
1619 _M_single_bucket = nullptr;
1620 _M_buckets = &_M_single_bucket;
1621 _M_before_begin._M_nxt = nullptr;
1622 _M_element_count = 0;
1623 }
1624
1625 template<typename _Key, typename _Value, typename _Alloc,
1626 typename _ExtractKey, typename _Equal,
1627 typename _Hash, typename _RangeHash, typename _Unused,
1628 typename _RehashPolicy, typename _Traits>
1629 void
1630 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1631 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1632 _M_move_assign(_Hashtable&& __ht, true_type)
1633 {
1634 if (__builtin_expect(std::__addressof(__ht) == this, false))
1635 return;
1636
1637 this->_M_deallocate_nodes(_M_begin());
1638 _M_deallocate_buckets();
1639 __hashtable_base::operator=(std::move(__ht));
1640 _M_rehash_policy = __ht._M_rehash_policy;
1641 if (!__ht._M_uses_single_bucket())
1642 _M_buckets = __ht._M_buckets;
1643 else
1644 {
1645 _M_buckets = &_M_single_bucket;
1646 _M_single_bucket = __ht._M_single_bucket;
1647 }
1648
1649 _M_bucket_count = __ht._M_bucket_count;
1650 _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1651 _M_element_count = __ht._M_element_count;
1652 std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
1653
1654 // Fix bucket containing the _M_before_begin pointer that can't be moved.
1655 _M_update_bbegin();
1656 __ht._M_reset();
1657 }
1658
1659 template<typename _Key, typename _Value, typename _Alloc,
1660 typename _ExtractKey, typename _Equal,
1661 typename _Hash, typename _RangeHash, typename _Unused,
1662 typename _RehashPolicy, typename _Traits>
1663 void
1664 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1665 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1666 _M_move_assign(_Hashtable&& __ht, false_type)
1667 {
1668 if (__ht._M_node_allocator() == this->_M_node_allocator())
1669 _M_move_assign(std::move(__ht), true_type{});
1670 else
1671 {
1672 // Can't move memory, move elements then.
1673 _M_assign_elements(std::move(__ht));
1674 __ht.clear();
1675 }
1676 }
1677
1678 template<typename _Key, typename _Value, typename _Alloc,
1679 typename _ExtractKey, typename _Equal,
1680 typename _Hash, typename _RangeHash, typename _Unused,
1681 typename _RehashPolicy, typename _Traits>
1682 inline
1683 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1684 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1685 _Hashtable(const _Hashtable& __ht)
1686 : __hashtable_base(__ht),
1687 __map_base(__ht),
1688 __rehash_base(__ht),
1689 __hashtable_alloc(
1690 __node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
1691 __enable_default_ctor(__ht),
1692 _M_buckets(nullptr),
1693 _M_bucket_count(__ht._M_bucket_count),
1694 _M_element_count(__ht._M_element_count),
1695 _M_rehash_policy(__ht._M_rehash_policy)
1696 {
1697 _M_assign(__ht);
1698 }
1699
1700 template<typename _Key, typename _Value, typename _Alloc,
1701 typename _ExtractKey, typename _Equal,
1702 typename _Hash, typename _RangeHash, typename _Unused,
1703 typename _RehashPolicy, typename _Traits>
1704 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1705 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1706 _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1707 true_type /* alloc always equal */)
1708 noexcept(_S_nothrow_move())
1709 : __hashtable_base(__ht),
1710 __map_base(__ht),
1711 __rehash_base(__ht),
1712 __hashtable_alloc(std::move(__a)),
1713 __enable_default_ctor(__ht),
1714 _M_buckets(__ht._M_buckets),
1715 _M_bucket_count(__ht._M_bucket_count),
1716 _M_before_begin(__ht._M_before_begin._M_nxt),
1717 _M_element_count(__ht._M_element_count),
1718 _M_rehash_policy(__ht._M_rehash_policy)
1719 {
1720 // Update buckets if __ht is using its single bucket.
1721 if (__ht._M_uses_single_bucket())
1722 {
1723 _M_buckets = &_M_single_bucket;
1724 _M_single_bucket = __ht._M_single_bucket;
1725 }
1726
1727 // Fix bucket containing the _M_before_begin pointer that can't be moved.
1728 _M_update_bbegin();
1729
1730 __ht._M_reset();
1731 }
1732
1733 template<typename _Key, typename _Value, typename _Alloc,
1734 typename _ExtractKey, typename _Equal,
1735 typename _Hash, typename _RangeHash, typename _Unused,
1736 typename _RehashPolicy, typename _Traits>
1737 inline
1738 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1739 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1740 _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
1741 : __hashtable_base(__ht),
1742 __map_base(__ht),
1743 __rehash_base(__ht),
1744 __hashtable_alloc(__node_alloc_type(__a)),
1745 __enable_default_ctor(__ht),
1746 _M_buckets(),
1747 _M_bucket_count(__ht._M_bucket_count),
1748 _M_element_count(__ht._M_element_count),
1749 _M_rehash_policy(__ht._M_rehash_policy)
1750 {
1751 _M_assign(__ht);
1752 }
1753
1754 template<typename _Key, typename _Value, typename _Alloc,
1755 typename _ExtractKey, typename _Equal,
1756 typename _Hash, typename _RangeHash, typename _Unused,
1757 typename _RehashPolicy, typename _Traits>
1758 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1759 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1760 _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1761 false_type /* alloc always equal */)
1762 : __hashtable_base(__ht),
1763 __map_base(__ht),
1764 __rehash_base(__ht),
1765 __hashtable_alloc(std::move(__a)),
1766 __enable_default_ctor(__ht),
1767 _M_buckets(nullptr),
1768 _M_bucket_count(__ht._M_bucket_count),
1769 _M_element_count(__ht._M_element_count),
1770 _M_rehash_policy(__ht._M_rehash_policy)
1771 {
1772 if (__ht._M_node_allocator() == this->_M_node_allocator())
1773 {
1774 if (__ht._M_uses_single_bucket())
1775 {
1776 _M_buckets = &_M_single_bucket;
1777 _M_single_bucket = __ht._M_single_bucket;
1778 }
1779 else
1780 _M_buckets = __ht._M_buckets;
1781
1782 // Fix bucket containing the _M_before_begin pointer that can't be
1783 // moved.
1784 _M_update_bbegin(__ht._M_begin());
1785
1786 __ht._M_reset();
1787 }
1788 else
1789 {
1790 using _Fwd_Ht = __conditional_t<
1791 __move_if_noexcept_cond<value_type>::value,
1792 const _Hashtable&, _Hashtable&&>;
1793 _M_assign(std::forward<_Fwd_Ht>(__ht));
1794 __ht.clear();
1795 }
1796 }
1797
1798 template<typename _Key, typename _Value, typename _Alloc,
1799 typename _ExtractKey, typename _Equal,
1800 typename _Hash, typename _RangeHash, typename _Unused,
1801 typename _RehashPolicy, typename _Traits>
1802 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1803 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1804 ~_Hashtable() noexcept
1805 {
1806 // Getting a bucket index from a node shall not throw because it is used
1807 // during the rehash process. This static_assert purpose is limited to usage
1808 // of _Hashtable with _Hashtable_traits requesting non-cached hash code.
1809 // Need a complete type to check this, so do it in the destructor not at
1810 // class scope.
1811 static_assert(noexcept(declval<const __hash_code_base_access&>()
1812 ._M_bucket_index(declval<const __node_value_type&>(),
1813 (std::size_t)0)),
1814 "Cache the hash code or qualify your functors involved"
1815 " in hash code and bucket index computation with noexcept");
1816
1817 this->_M_deallocate_nodes(_M_begin());
1818 _M_deallocate_buckets();
1819 }
1820
1821 template<typename _Key, typename _Value, typename _Alloc,
1822 typename _ExtractKey, typename _Equal,
1823 typename _Hash, typename _RangeHash, typename _Unused,
1824 typename _RehashPolicy, typename _Traits>
1825 void
1826 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1827 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1828 swap(_Hashtable& __x)
1829 noexcept(__and_<__is_nothrow_swappable<_Hash>,
1830 __is_nothrow_swappable<_Equal>>::value)
1831 {
1832 // The only base class with member variables is hash_code_base.
1833 // We define _Hash_code_base::_M_swap because different
1834 // specializations have different members.
1835 this->_M_swap(__x);
1836
1837 std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
1838 std::swap(_M_rehash_policy, __x._M_rehash_policy);
1839
1840 // Deal properly with potentially moved instances.
1841 if (this->_M_uses_single_bucket())
1842 {
1843 if (!__x._M_uses_single_bucket())
1844 {
1845 _M_buckets = __x._M_buckets;
1846 __x._M_buckets = &__x._M_single_bucket;
1847 }
1848 }
1849 else if (__x._M_uses_single_bucket())
1850 {
1851 __x._M_buckets = _M_buckets;
1852 _M_buckets = &_M_single_bucket;
1853 }
1854 else
1855 std::swap(_M_buckets, __x._M_buckets);
1856
1857 std::swap(_M_bucket_count, __x._M_bucket_count);
1858 std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
1859 std::swap(_M_element_count, __x._M_element_count);
1860 std::swap(_M_single_bucket, __x._M_single_bucket);
1861
1862 // Fix buckets containing the _M_before_begin pointers that can't be
1863 // swapped.
1864 _M_update_bbegin();
1865 __x._M_update_bbegin();
1866 }
1867
1868 template<typename _Key, typename _Value, typename _Alloc,
1869 typename _ExtractKey, typename _Equal,
1870 typename _Hash, typename _RangeHash, typename _Unused,
1871 typename _RehashPolicy, typename _Traits>
1872 auto
1873 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1874 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1875 find(const key_type& __k)
1876 -> iterator
1877 { return iterator(_M_locate(__k)); }
1878
1879 template<typename _Key, typename _Value, typename _Alloc,
1880 typename _ExtractKey, typename _Equal,
1881 typename _Hash, typename _RangeHash, typename _Unused,
1882 typename _RehashPolicy, typename _Traits>
1883 auto
1884 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1885 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1886 find(const key_type& __k) const
1887 -> const_iterator
1888 { return const_iterator(_M_locate(__k)); }
1889
1890#if __cplusplus > 201703L
1891 template<typename _Key, typename _Value, typename _Alloc,
1892 typename _ExtractKey, typename _Equal,
1893 typename _Hash, typename _RangeHash, typename _Unused,
1894 typename _RehashPolicy, typename _Traits>
1895 template<typename _Kt, typename, typename>
1896 auto
1897 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1898 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1899 _M_find_tr(const _Kt& __k)
1900 -> iterator
1901 {
1902 if (size() <= __small_size_threshold())
1903 {
1904 for (auto __n = _M_begin(); __n; __n = __n->_M_next())
1905 if (this->_M_key_equals_tr(__k, *__n))
1906 return iterator(__n);
1907 return end();
1908 }
1909
1910 __hash_code __code = this->_M_hash_code_tr(__k);
1911 std::size_t __bkt = _M_bucket_index(__code);
1912 return iterator(_M_find_node_tr(__bkt, __k, __code));
1913 }
1914
1915 template<typename _Key, typename _Value, typename _Alloc,
1916 typename _ExtractKey, typename _Equal,
1917 typename _Hash, typename _RangeHash, typename _Unused,
1918 typename _RehashPolicy, typename _Traits>
1919 template<typename _Kt, typename, typename>
1920 auto
1921 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1922 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1923 _M_find_tr(const _Kt& __k) const
1924 -> const_iterator
1925 {
1926 if (size() <= __small_size_threshold())
1927 {
1928 for (auto __n = _M_begin(); __n; __n = __n->_M_next())
1929 if (this->_M_key_equals_tr(__k, *__n))
1930 return const_iterator(__n);
1931 return end();
1932 }
1933
1934 __hash_code __code = this->_M_hash_code_tr(__k);
1935 std::size_t __bkt = _M_bucket_index(__code);
1936 return const_iterator(_M_find_node_tr(__bkt, __k, __code));
1937 }
1938#endif
1939
1940 template<typename _Key, typename _Value, typename _Alloc,
1941 typename _ExtractKey, typename _Equal,
1942 typename _Hash, typename _RangeHash, typename _Unused,
1943 typename _RehashPolicy, typename _Traits>
1944 auto
1945 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1946 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1947 count(const key_type& __k) const
1948 -> size_type
1949 {
1950 auto __it = find(__k);
1951 if (!__it._M_cur)
1952 return 0;
1953
1954 if (__unique_keys::value)
1955 return 1;
1956
1957 size_type __result = 1;
1958 for (auto __ref = __it++;
1959 __it._M_cur && this->_M_node_equals(*__ref._M_cur, *__it._M_cur);
1960 ++__it)
1961 ++__result;
1962
1963 return __result;
1964 }
1965
1966#if __cplusplus > 201703L
1967 template<typename _Key, typename _Value, typename _Alloc,
1968 typename _ExtractKey, typename _Equal,
1969 typename _Hash, typename _RangeHash, typename _Unused,
1970 typename _RehashPolicy, typename _Traits>
1971 template<typename _Kt, typename, typename>
1972 auto
1973 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1974 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1975 _M_count_tr(const _Kt& __k) const
1976 -> size_type
1977 {
1978 if (size() <= __small_size_threshold())
1979 {
1980 size_type __result = 0;
1981 for (auto __n = _M_begin(); __n; __n = __n->_M_next())
1982 {
1983 if (this->_M_key_equals_tr(__k, *__n))
1984 {
1985 ++__result;
1986 continue;
1987 }
1988
1989 if (__result)
1990 break;
1991 }
1992
1993 return __result;
1994 }
1995
1996 __hash_code __code = this->_M_hash_code_tr(__k);
1997 std::size_t __bkt = _M_bucket_index(__code);
1998 auto __n = _M_find_node_tr(__bkt, __k, __code);
1999 if (!__n)
2000 return 0;
2001
2002 iterator __it(__n);
2003 size_type __result = 1;
2004 for (++__it;
2005 __it._M_cur && this->_M_equals_tr(__k, __code, *__it._M_cur);
2006 ++__it)
2007 ++__result;
2008
2009 return __result;
2010 }
2011#endif
2012
2013 template<typename _Key, typename _Value, typename _Alloc,
2014 typename _ExtractKey, typename _Equal,
2015 typename _Hash, typename _RangeHash, typename _Unused,
2016 typename _RehashPolicy, typename _Traits>
2017 auto
2018 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2019 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2020 equal_range(const key_type& __k)
2021 -> pair<iterator, iterator>
2022 {
2023 auto __ite = find(__k);
2024 if (!__ite._M_cur)
2025 return { __ite, __ite };
2026
2027 auto __beg = __ite++;
2028 if (__unique_keys::value)
2029 return { __beg, __ite };
2030
2031 while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
2032 ++__ite;
2033
2034 return { __beg, __ite };
2035 }
2036
2037 template<typename _Key, typename _Value, typename _Alloc,
2038 typename _ExtractKey, typename _Equal,
2039 typename _Hash, typename _RangeHash, typename _Unused,
2040 typename _RehashPolicy, typename _Traits>
2041 auto
2042 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2043 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2044 equal_range(const key_type& __k) const
2045 -> pair<const_iterator, const_iterator>
2046 {
2047 auto __ite = find(__k);
2048 if (!__ite._M_cur)
2049 return { __ite, __ite };
2050
2051 auto __beg = __ite++;
2052 if (__unique_keys::value)
2053 return { __beg, __ite };
2054
2055 while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
2056 ++__ite;
2057
2058 return { __beg, __ite };
2059 }
2060
2061#if __cplusplus > 201703L
2062 template<typename _Key, typename _Value, typename _Alloc,
2063 typename _ExtractKey, typename _Equal,
2064 typename _Hash, typename _RangeHash, typename _Unused,
2065 typename _RehashPolicy, typename _Traits>
2066 template<typename _Kt, typename, typename>
2067 auto
2068 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2069 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2070 _M_equal_range_tr(const _Kt& __k)
2071 -> pair<iterator, iterator>
2072 {
2073 if (size() <= __small_size_threshold())
2074 {
2075 __node_ptr __n, __beg = nullptr;
2076 for (__n = _M_begin(); __n; __n = __n->_M_next())
2077 {
2078 if (this->_M_key_equals_tr(__k, *__n))
2079 {
2080 if (!__beg)
2081 __beg = __n;
2082 continue;
2083 }
2084
2085 if (__beg)
2086 break;
2087 }
2088
2089 return { iterator(__beg), iterator(__n) };
2090 }
2091
2092 __hash_code __code = this->_M_hash_code_tr(__k);
2093 std::size_t __bkt = _M_bucket_index(__code);
2094 auto __n = _M_find_node_tr(__bkt, __k, __code);
2095 iterator __ite(__n);
2096 if (!__n)
2097 return { __ite, __ite };
2098
2099 auto __beg = __ite++;
2100 while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
2101 ++__ite;
2102
2103 return { __beg, __ite };
2104 }
2105
2106 template<typename _Key, typename _Value, typename _Alloc,
2107 typename _ExtractKey, typename _Equal,
2108 typename _Hash, typename _RangeHash, typename _Unused,
2109 typename _RehashPolicy, typename _Traits>
2110 template<typename _Kt, typename, typename>
2111 auto
2112 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2113 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2114 _M_equal_range_tr(const _Kt& __k) const
2115 -> pair<const_iterator, const_iterator>
2116 {
2117 if (size() <= __small_size_threshold())
2118 {
2119 __node_ptr __n, __beg = nullptr;
2120 for (__n = _M_begin(); __n; __n = __n->_M_next())
2121 {
2122 if (this->_M_key_equals_tr(__k, *__n))
2123 {
2124 if (!__beg)
2125 __beg = __n;
2126 continue;
2127 }
2128
2129 if (__beg)
2130 break;
2131 }
2132
2133 return { const_iterator(__beg), const_iterator(__n) };
2134 }
2135
2136 __hash_code __code = this->_M_hash_code_tr(__k);
2137 std::size_t __bkt = _M_bucket_index(__code);
2138 auto __n = _M_find_node_tr(__bkt, __k, __code);
2139 const_iterator __ite(__n);
2140 if (!__n)
2141 return { __ite, __ite };
2142
2143 auto __beg = __ite++;
2144 while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
2145 ++__ite;
2146
2147 return { __beg, __ite };
2148 }
2149#endif
2150
2151 // Find the node before the one whose key compares equal to k in the bucket
2152 // bkt. Return nullptr if no node is found.
2153 template<typename _Key, typename _Value, typename _Alloc,
2154 typename _ExtractKey, typename _Equal,
2155 typename _Hash, typename _RangeHash, typename _Unused,
2156 typename _RehashPolicy, typename _Traits>
2157 auto
2158 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2159 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2160 _M_find_before_node(size_type __bkt, const key_type& __k,
2161 __hash_code __code) const
2162 -> __node_base_ptr
2163 {
2164 __node_base_ptr __prev_p = _M_buckets[__bkt];
2165 if (!__prev_p)
2166 return nullptr;
2167
2168 for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
2169 __p = __p->_M_next())
2170 {
2171 if (this->_M_equals(__k, __code, *__p))
2172 return __prev_p;
2173
2174 if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
2175 break;
2176 __prev_p = __p;
2177 }
2178
2179 return nullptr;
2180 }
2181
2182 template<typename _Key, typename _Value, typename _Alloc,
2183 typename _ExtractKey, typename _Equal,
2184 typename _Hash, typename _RangeHash, typename _Unused,
2185 typename _RehashPolicy, typename _Traits>
2186 template<typename _Kt>
2187 auto
2188 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2189 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2190 _M_find_before_node_tr(size_type __bkt, const _Kt& __k,
2191 __hash_code __code) const
2192 -> __node_base_ptr
2193 {
2194 __node_base_ptr __prev_p = _M_buckets[__bkt];
2195 if (!__prev_p)
2196 return nullptr;
2197
2198 for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
2199 __p = __p->_M_next())
2200 {
2201 if (this->_M_equals_tr(__k, __code, *__p))
2202 return __prev_p;
2203
2204 if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
2205 break;
2206 __prev_p = __p;
2207 }
2208
2209 return nullptr;
2210 }
2211
2212 template<typename _Key, typename _Value, typename _Alloc,
2213 typename _ExtractKey, typename _Equal,
2214 typename _Hash, typename _RangeHash, typename _Unused,
2215 typename _RehashPolicy, typename _Traits>
2216 auto
2217 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2218 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2219 _M_locate(const key_type& __k) const
2220 -> __location_type
2221 {
2222 __location_type __loc;
2223 const auto __size = size();
2224
2225 if (__size <= __small_size_threshold())
2226 {
2227 __loc._M_before = pointer_traits<__node_base_ptr>::
2228 pointer_to(const_cast<__node_base&>(_M_before_begin));
2229 while (__loc._M_before->_M_nxt)
2230 {
2231 if (this->_M_key_equals(__k, *__loc._M_node()))
2232 return __loc;
2233 __loc._M_before = __loc._M_before->_M_nxt;
2234 }
2235 __loc._M_before = nullptr; // Didn't find it.
2236 }
2237
2238 __loc._M_hash_code = this->_M_hash_code(__k);
2239 __loc._M_bucket_index = _M_bucket_index(__loc._M_hash_code);
2240
2241 if (__size > __small_size_threshold())
2242 __loc._M_before = _M_find_before_node(__loc._M_bucket_index, __k,
2243 __loc._M_hash_code);
2244
2245 return __loc;
2246 }
2247
2248 template<typename _Key, typename _Value, typename _Alloc,
2249 typename _ExtractKey, typename _Equal,
2250 typename _Hash, typename _RangeHash, typename _Unused,
2251 typename _RehashPolicy, typename _Traits>
2252 auto
2253 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2254 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2255 _M_get_previous_node(size_type __bkt, __node_ptr __n)
2256 -> __node_base_ptr
2257 {
2258 __node_base_ptr __prev_n = _M_buckets[__bkt];
2259 while (__prev_n->_M_nxt != __n)
2260 __prev_n = __prev_n->_M_nxt;
2261 return __prev_n;
2262 }
2263
2264#pragma GCC diagnostic push
2265#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
2266 template<typename _Key, typename _Value, typename _Alloc,
2267 typename _ExtractKey, typename _Equal,
2268 typename _Hash, typename _RangeHash, typename _Unused,
2269 typename _RehashPolicy, typename _Traits>
2270 template<typename... _Args>
2271 auto
2272 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2273 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2274 _M_emplace_uniq(_Args&&... __args)
2275 -> pair<iterator, bool>
2276 {
2277 const key_type* __kp = nullptr;
2278
2279 if constexpr (sizeof...(_Args) == 1)
2280 {
2281 if constexpr (__is_key_type<_Args...>)
2282 {
2283 const auto& __key = _ExtractKey{}(__args...);
2284 __kp = std::__addressof(__key);
2285 }
2286 }
2287 else if constexpr (sizeof...(_Args) == 2)
2288 {
2289 if constexpr (__is_key_type<pair<const _Args&...>>)
2290 {
2291 pair<const _Args&...> __refs(__args...);
2292 const auto& __key = _ExtractKey{}(__refs);
2293 __kp = std::__addressof(__key);
2294 }
2295 }
2296
2297 _Scoped_node __node { __node_ptr(), this }; // Do not create node yet.
2298 __hash_code __code = 0;
2299 size_type __bkt = 0;
2300
2301 if (__kp == nullptr)
2302 {
2303 // Didn't extract a key from the args, so build the node.
2304 __node._M_node
2305 = this->_M_allocate_node(std::forward<_Args>(__args)...);
2306 const key_type& __key = _ExtractKey{}(__node._M_node->_M_v());
2307 __kp = std::__addressof(__key);
2308 }
2309
2310 if (auto __loc = _M_locate(*__kp))
2311 // There is already an equivalent node, no insertion.
2312 return { iterator(__loc), false };
2313 else
2314 {
2315 __code = __loc._M_hash_code;
2316 __bkt = __loc._M_bucket_index;
2317 }
2318
2319 if (!__node._M_node)
2320 __node._M_node
2321 = this->_M_allocate_node(std::forward<_Args>(__args)...);
2322
2323 // Insert the node
2324 auto __pos = _M_insert_unique_node(__bkt, __code, __node._M_node);
2325 __node._M_node = nullptr;
2326 return { __pos, true };
2327 }
2328#pragma GCC diagnostic pop
2329
2330 template<typename _Key, typename _Value, typename _Alloc,
2331 typename _ExtractKey, typename _Equal,
2332 typename _Hash, typename _RangeHash, typename _Unused,
2333 typename _RehashPolicy, typename _Traits>
2334 template<typename... _Args>
2335 auto
2336 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2337 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2338 _M_emplace_multi(const_iterator __hint, _Args&&... __args)
2339 -> iterator
2340 {
2341 // First build the node to get its hash code.
2342 _Scoped_node __node { this, std::forward<_Args>(__args)... };
2343 const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
2344
2345 auto __res = this->_M_compute_hash_code(__hint._M_cur, __k);
2346 auto __pos
2347 = _M_insert_multi_node(__res.first, __res.second, __node._M_node);
2348 __node._M_node = nullptr;
2349 return __pos;
2350 }
2351
2352 template<typename _Key, typename _Value, typename _Alloc,
2353 typename _ExtractKey, typename _Equal,
2354 typename _Hash, typename _RangeHash, typename _Unused,
2355 typename _RehashPolicy, typename _Traits>
2356 template<typename _InputIterator>
2357 void
2358 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2359 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2360 _M_insert_range_multi(_InputIterator __first, _InputIterator __last)
2361 {
2362 using __pair_type = std::pair<bool, std::size_t>;
2363
2364 size_type __n_elt = __detail::__distance_fw(__first, __last);
2365 if (__n_elt == 0)
2366 return;
2367
2368 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2369 __pair_type __do_rehash
2370 = _M_rehash_policy._M_need_rehash(_M_bucket_count,
2371 _M_element_count,
2372 __n_elt);
2373
2374 if (__do_rehash.first)
2375 _M_rehash(__do_rehash.second, false_type{});
2376
2377 __rehash_guard._M_guarded_obj = nullptr;
2378 for (; __first != __last; ++__first)
2379 _M_emplace_multi(cend(), *__first);
2380 }
2381
2382 template<typename _Key, typename _Value, typename _Alloc,
2383 typename _ExtractKey, typename _Equal,
2384 typename _Hash, typename _RangeHash, typename _Unused,
2385 typename _RehashPolicy, typename _Traits>
2386 auto
2387 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2388 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2389 _M_compute_hash_code(__node_ptr __hint, const key_type& __k) const
2390 -> pair<__node_ptr, __hash_code>
2391 {
2392 if (size() <= __small_size_threshold())
2393 {
2394 if (__hint)
2395 {
2396 for (auto __it = __hint; __it; __it = __it->_M_next())
2397 if (this->_M_key_equals(__k, *__it))
2398 return { __it, this->_M_hash_code(*__it) };
2399 }
2400
2401 for (auto __it = _M_begin(); __it != __hint; __it = __it->_M_next())
2402 if (this->_M_key_equals(__k, *__it))
2403 return { __it, this->_M_hash_code(*__it) };
2404
2405 __hint = nullptr;
2406 }
2407
2408 return { __hint, this->_M_hash_code(__k) };
2409 }
2410
2411 template<typename _Key, typename _Value, typename _Alloc,
2412 typename _ExtractKey, typename _Equal,
2413 typename _Hash, typename _RangeHash, typename _Unused,
2414 typename _RehashPolicy, typename _Traits>
2415 auto
2416 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2417 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2418 _M_insert_unique_node(size_type __bkt, __hash_code __code,
2419 __node_ptr __node, size_type __n_elt)
2420 -> iterator
2421 {
2422 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2424 = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count,
2425 __n_elt);
2426
2427 if (__do_rehash.first)
2428 {
2429 _M_rehash(__do_rehash.second, true_type{});
2430 __bkt = _M_bucket_index(__code);
2431 }
2432
2433 __rehash_guard._M_guarded_obj = nullptr;
2434 this->_M_store_code(*__node, __code);
2435
2436 // Always insert at the beginning of the bucket.
2437 _M_insert_bucket_begin(__bkt, __node);
2438 ++_M_element_count;
2439 return iterator(__node);
2440 }
2441
2442 template<typename _Key, typename _Value, typename _Alloc,
2443 typename _ExtractKey, typename _Equal,
2444 typename _Hash, typename _RangeHash, typename _Unused,
2445 typename _RehashPolicy, typename _Traits>
2446 auto
2447 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2448 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2449 _M_insert_multi_node(__node_ptr __hint,
2450 __hash_code __code, __node_ptr __node)
2451 -> iterator
2452 {
2453 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2455 = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
2456
2457 if (__do_rehash.first)
2458 _M_rehash(__do_rehash.second, false_type{});
2459
2460 __rehash_guard._M_guarded_obj = nullptr;
2461 this->_M_store_code(*__node, __code);
2462 const key_type& __k = _ExtractKey{}(__node->_M_v());
2463 size_type __bkt = _M_bucket_index(__code);
2464
2465 // Find the node before an equivalent one or use hint if it exists and
2466 // if it is equivalent.
2467 __node_base_ptr __prev
2468 = __builtin_expect(__hint != nullptr, false)
2469 && this->_M_equals(__k, __code, *__hint)
2470 ? __hint
2471 : _M_find_before_node(__bkt, __k, __code);
2472
2473 if (__prev)
2474 {
2475 // Insert after the node before the equivalent one.
2476 __node->_M_nxt = __prev->_M_nxt;
2477 __prev->_M_nxt = __node;
2478 if (__builtin_expect(__prev == __hint, false))
2479 // hint might be the last bucket node, in this case we need to
2480 // update next bucket.
2481 if (__node->_M_nxt
2482 && !this->_M_equals(__k, __code, *__node->_M_next()))
2483 {
2484 size_type __next_bkt = _M_bucket_index(*__node->_M_next());
2485 if (__next_bkt != __bkt)
2486 _M_buckets[__next_bkt] = __node;
2487 }
2488 }
2489 else
2490 // The inserted node has no equivalent in the hashtable. We must
2491 // insert the new node at the beginning of the bucket to preserve
2492 // equivalent elements' relative positions.
2493 _M_insert_bucket_begin(__bkt, __node);
2494 ++_M_element_count;
2495 return iterator(__node);
2496 }
2497
2498 template<typename _Key, typename _Value, typename _Alloc,
2499 typename _ExtractKey, typename _Equal,
2500 typename _Hash, typename _RangeHash, typename _Unused,
2501 typename _RehashPolicy, typename _Traits>
2502 auto
2503 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2504 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2505 erase(const_iterator __it)
2506 -> iterator
2507 {
2508 __node_ptr __n = __it._M_cur;
2509 std::size_t __bkt = _M_bucket_index(*__n);
2510
2511 // Look for previous node to unlink it from the erased one, this
2512 // is why we need buckets to contain the before begin to make
2513 // this search fast.
2514 __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2515 return _M_erase(__bkt, __prev_n, __n);
2516 }
2517
2518 template<typename _Key, typename _Value, typename _Alloc,
2519 typename _ExtractKey, typename _Equal,
2520 typename _Hash, typename _RangeHash, typename _Unused,
2521 typename _RehashPolicy, typename _Traits>
2522 auto
2523 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2524 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2525 _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n)
2526 -> iterator
2527 {
2528 if (__prev_n == _M_buckets[__bkt])
2529 _M_remove_bucket_begin(__bkt, __n->_M_next(),
2530 __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
2531 else if (__n->_M_nxt)
2532 {
2533 size_type __next_bkt = _M_bucket_index(*__n->_M_next());
2534 if (__next_bkt != __bkt)
2535 _M_buckets[__next_bkt] = __prev_n;
2536 }
2537
2538 __prev_n->_M_nxt = __n->_M_nxt;
2539 iterator __result(__n->_M_next());
2540 this->_M_deallocate_node(__n);
2541 --_M_element_count;
2542
2543 return __result;
2544 }
2545
2546#pragma GCC diagnostic push
2547#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
2548 template<typename _Key, typename _Value, typename _Alloc,
2549 typename _ExtractKey, typename _Equal,
2550 typename _Hash, typename _RangeHash, typename _Unused,
2551 typename _RehashPolicy, typename _Traits>
2552 auto
2553 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2554 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2555 erase(const key_type& __k)
2556 -> size_type
2557 {
2558 auto __loc = _M_locate(__k);
2559 if (!__loc)
2560 return 0;
2561
2562 __node_base_ptr __prev_n = __loc._M_before;
2563 __node_ptr __n = __loc._M_node();
2564 auto __bkt = __loc._M_bucket_index;
2565 if (__bkt == size_type(-1))
2566 __bkt = _M_bucket_index(*__n);
2567
2568 if constexpr (__unique_keys::value)
2569 {
2570 _M_erase(__bkt, __prev_n, __n);
2571 return 1;
2572 }
2573 else
2574 {
2575 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2576 // 526. Is it undefined if a function in the standard changes
2577 // in parameters?
2578 // We use one loop to find all matching nodes and another to
2579 // deallocate them so that the key stays valid during the first loop.
2580 // It might be invalidated indirectly when destroying nodes.
2581 __node_ptr __n_last = __n->_M_next();
2582 while (__n_last && this->_M_node_equals(*__n, *__n_last))
2583 __n_last = __n_last->_M_next();
2584
2585 std::size_t __n_last_bkt
2586 = __n_last ? _M_bucket_index(*__n_last) : __bkt;
2587
2588 // Deallocate nodes.
2589 size_type __result = 0;
2590 do
2591 {
2592 __node_ptr __p = __n->_M_next();
2593 this->_M_deallocate_node(__n);
2594 __n = __p;
2595 ++__result;
2596 }
2597 while (__n != __n_last);
2598
2599 _M_element_count -= __result;
2600 if (__prev_n == _M_buckets[__bkt])
2601 _M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
2602 else if (__n_last_bkt != __bkt)
2603 _M_buckets[__n_last_bkt] = __prev_n;
2604 __prev_n->_M_nxt = __n_last;
2605 return __result;
2606 }
2607 }
2608#pragma GCC diagnostic pop
2609
2610 template<typename _Key, typename _Value, typename _Alloc,
2611 typename _ExtractKey, typename _Equal,
2612 typename _Hash, typename _RangeHash, typename _Unused,
2613 typename _RehashPolicy, typename _Traits>
2614 auto
2615 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2616 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2617 erase(const_iterator __first, const_iterator __last)
2618 -> iterator
2619 {
2620 __node_ptr __n = __first._M_cur;
2621 __node_ptr __last_n = __last._M_cur;
2622 if (__n == __last_n)
2623 return iterator(__n);
2624
2625 std::size_t __bkt = _M_bucket_index(*__n);
2626
2627 __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2628 bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
2629 std::size_t __n_bkt = __bkt;
2630 for (;;)
2631 {
2632 do
2633 {
2634 __node_ptr __tmp = __n;
2635 __n = __n->_M_next();
2636 this->_M_deallocate_node(__tmp);
2637 --_M_element_count;
2638 if (!__n)
2639 break;
2640 __n_bkt = _M_bucket_index(*__n);
2641 }
2642 while (__n != __last_n && __n_bkt == __bkt);
2643 if (__is_bucket_begin)
2644 _M_remove_bucket_begin(__bkt, __n, __n_bkt);
2645 if (__n == __last_n)
2646 break;
2647 __is_bucket_begin = true;
2648 __bkt = __n_bkt;
2649 }
2650
2651 if (__n && (__n_bkt != __bkt || __is_bucket_begin))
2652 _M_buckets[__n_bkt] = __prev_n;
2653 __prev_n->_M_nxt = __n;
2654 return iterator(__n);
2655 }
2656
2657 template<typename _Key, typename _Value, typename _Alloc,
2658 typename _ExtractKey, typename _Equal,
2659 typename _Hash, typename _RangeHash, typename _Unused,
2660 typename _RehashPolicy, typename _Traits>
2661 void
2662 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2663 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2664 clear() noexcept
2665 {
2666 this->_M_deallocate_nodes(_M_begin());
2667 std::fill_n(_M_buckets, _M_bucket_count, nullptr);
2668 _M_element_count = 0;
2669 _M_before_begin._M_nxt = nullptr;
2670 }
2671
2672 template<typename _Key, typename _Value, typename _Alloc,
2673 typename _ExtractKey, typename _Equal,
2674 typename _Hash, typename _RangeHash, typename _Unused,
2675 typename _RehashPolicy, typename _Traits>
2676 void
2677 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2678 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2679 rehash(size_type __bkt_count)
2680 {
2681 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2682 __bkt_count
2683 = std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
2684 __bkt_count);
2685 __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count);
2686
2687 if (__bkt_count != _M_bucket_count)
2688 {
2689 _M_rehash(__bkt_count, __unique_keys{});
2690 __rehash_guard._M_guarded_obj = nullptr;
2691 }
2692 }
2693
2694 // Rehash when there is no equivalent elements.
2695 template<typename _Key, typename _Value, typename _Alloc,
2696 typename _ExtractKey, typename _Equal,
2697 typename _Hash, typename _RangeHash, typename _Unused,
2698 typename _RehashPolicy, typename _Traits>
2699 void
2700 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2701 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2702 _M_rehash(size_type __bkt_count, true_type /* __uks */)
2703 {
2704 __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2705 __node_ptr __p = _M_begin();
2706 _M_before_begin._M_nxt = nullptr;
2707 std::size_t __bbegin_bkt = 0;
2708 while (__p)
2709 {
2710 __node_ptr __next = __p->_M_next();
2711 std::size_t __bkt
2712 = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2713 if (!__new_buckets[__bkt])
2714 {
2715 __p->_M_nxt = _M_before_begin._M_nxt;
2716 _M_before_begin._M_nxt = __p;
2717 __new_buckets[__bkt] = &_M_before_begin;
2718 if (__p->_M_nxt)
2719 __new_buckets[__bbegin_bkt] = __p;
2720 __bbegin_bkt = __bkt;
2721 }
2722 else
2723 {
2724 __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2725 __new_buckets[__bkt]->_M_nxt = __p;
2726 }
2727
2728 __p = __next;
2729 }
2730
2731 _M_deallocate_buckets();
2732 _M_bucket_count = __bkt_count;
2733 _M_buckets = __new_buckets;
2734 }
2735
2736 // Rehash when there can be equivalent elements, preserve their relative
2737 // order.
2738 template<typename _Key, typename _Value, typename _Alloc,
2739 typename _ExtractKey, typename _Equal,
2740 typename _Hash, typename _RangeHash, typename _Unused,
2741 typename _RehashPolicy, typename _Traits>
2742 void
2743 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2744 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2745 _M_rehash(size_type __bkt_count, false_type /* __uks */)
2746 {
2747 __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2748 __node_ptr __p = _M_begin();
2749 _M_before_begin._M_nxt = nullptr;
2750 std::size_t __bbegin_bkt = 0;
2751 std::size_t __prev_bkt = 0;
2752 __node_ptr __prev_p = nullptr;
2753 bool __check_bucket = false;
2754
2755 while (__p)
2756 {
2757 __node_ptr __next = __p->_M_next();
2758 std::size_t __bkt
2759 = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2760
2761 if (__prev_p && __prev_bkt == __bkt)
2762 {
2763 // Previous insert was already in this bucket, we insert after
2764 // the previously inserted one to preserve equivalent elements
2765 // relative order.
2766 __p->_M_nxt = __prev_p->_M_nxt;
2767 __prev_p->_M_nxt = __p;
2768
2769 // Inserting after a node in a bucket require to check that we
2770 // haven't change the bucket last node, in this case next
2771 // bucket containing its before begin node must be updated. We
2772 // schedule a check as soon as we move out of the sequence of
2773 // equivalent nodes to limit the number of checks.
2774 __check_bucket = true;
2775 }
2776 else
2777 {
2778 if (__check_bucket)
2779 {
2780 // Check if we shall update the next bucket because of
2781 // insertions into __prev_bkt bucket.
2782 if (__prev_p->_M_nxt)
2783 {
2784 std::size_t __next_bkt
2785 = __hash_code_base::_M_bucket_index(
2786 *__prev_p->_M_next(), __bkt_count);
2787 if (__next_bkt != __prev_bkt)
2788 __new_buckets[__next_bkt] = __prev_p;
2789 }
2790 __check_bucket = false;
2791 }
2792
2793 if (!__new_buckets[__bkt])
2794 {
2795 __p->_M_nxt = _M_before_begin._M_nxt;
2796 _M_before_begin._M_nxt = __p;
2797 __new_buckets[__bkt] = &_M_before_begin;
2798 if (__p->_M_nxt)
2799 __new_buckets[__bbegin_bkt] = __p;
2800 __bbegin_bkt = __bkt;
2801 }
2802 else
2803 {
2804 __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2805 __new_buckets[__bkt]->_M_nxt = __p;
2806 }
2807 }
2808 __prev_p = __p;
2809 __prev_bkt = __bkt;
2810 __p = __next;
2811 }
2812
2813 if (__check_bucket && __prev_p->_M_nxt)
2814 {
2815 std::size_t __next_bkt
2816 = __hash_code_base::_M_bucket_index(*__prev_p->_M_next(),
2817 __bkt_count);
2818 if (__next_bkt != __prev_bkt)
2819 __new_buckets[__next_bkt] = __prev_p;
2820 }
2821
2822 _M_deallocate_buckets();
2823 _M_bucket_count = __bkt_count;
2824 _M_buckets = __new_buckets;
2825 }
2826
2827#pragma GCC diagnostic push
2828#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
2829
2830 // This is for implementing equality comparison for unordered containers,
2831 // per N3068, by John Lakos and Pablo Halpern.
2832 // Algorithmically, we follow closely the reference implementations therein.
2833 template<typename _Key, typename _Value, typename _Alloc,
2834 typename _ExtractKey, typename _Equal,
2835 typename _Hash, typename _RangeHash, typename _Unused,
2836 typename _RehashPolicy, typename _Traits>
2837 bool
2838 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2839 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2840 _M_equal(const _Hashtable& __other) const
2841 {
2842 if (size() != __other.size())
2843 return false;
2844
2845 if constexpr (__unique_keys::value)
2846 for (auto __x_n = _M_begin(); __x_n; __x_n = __x_n->_M_next())
2847 {
2848 std::size_t __ybkt = __other._M_bucket_index(*__x_n);
2849 auto __prev_n = __other._M_buckets[__ybkt];
2850 if (!__prev_n)
2851 return false;
2852
2853 for (__node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);;
2854 __n = __n->_M_next())
2855 {
2856 if (__n->_M_v() == __x_n->_M_v())
2857 break;
2858
2859 if (!__n->_M_nxt
2860 || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
2861 return false;
2862 }
2863 }
2864 else // non-unique keys
2865 for (auto __x_n = _M_begin(); __x_n;)
2866 {
2867 std::size_t __x_count = 1;
2868 auto __x_n_end = __x_n->_M_next();
2869 for (; __x_n_end
2870 && key_eq()(_ExtractKey{}(__x_n->_M_v()),
2871 _ExtractKey{}(__x_n_end->_M_v()));
2872 __x_n_end = __x_n_end->_M_next())
2873 ++__x_count;
2874
2875 std::size_t __ybkt = __other._M_bucket_index(*__x_n);
2876 auto __y_prev_n = __other._M_buckets[__ybkt];
2877 if (!__y_prev_n)
2878 return false;
2879
2880 __node_ptr __y_n = static_cast<__node_ptr>(__y_prev_n->_M_nxt);
2881 for (;;)
2882 {
2883 if (key_eq()(_ExtractKey{}(__y_n->_M_v()),
2884 _ExtractKey{}(__x_n->_M_v())))
2885 break;
2886
2887 auto __y_ref_n = __y_n;
2888 for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
2889 if (!__other._M_node_equals(*__y_ref_n, *__y_n))
2890 break;
2891
2892 if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
2893 return false;
2894 }
2895
2896 auto __y_n_end = __y_n;
2897 for (; __y_n_end; __y_n_end = __y_n_end->_M_next())
2898 if (--__x_count == 0)
2899 break;
2900
2901 if (__x_count != 0)
2902 return false;
2903
2904 const_iterator __itx(__x_n), __itx_end(__x_n_end);
2905 const_iterator __ity(__y_n);
2906 if (!std::is_permutation(__itx, __itx_end, __ity))
2907 return false;
2908
2909 __x_n = __x_n_end;
2910 }
2911
2912 return true;
2913 }
2914#pragma GCC diagnostic pop
2915
2916#if __cplusplus > 201402L
2917 template<typename, typename, typename> class _Hash_merge_helper { };
2918#endif // C++17
2919
2920#if __cpp_deduction_guides >= 201606
2921 // Used to constrain deduction guides
2922 template<typename _Hash>
2923 using _RequireNotAllocatorOrIntegral
2924 = __enable_if_t<!__or_<is_integral<_Hash>, __is_allocator<_Hash>>::value>;
2925#endif
2926
2927/// @endcond
2928_GLIBCXX_END_NAMESPACE_VERSION
2929} // namespace std
2930
2931#pragma GCC diagnostic pop
2932
2933#endif // _HASHTABLE_H
pair(_T1, _T2) -> pair< _T1, _T2 >
Two pairs are equal iff their members are equal.
auto declval() noexcept -> decltype(__declval< _Tp >(0))
Definition type_traits:2600
constexpr tuple< _Elements &&... > forward_as_tuple(_Elements &&... __args) noexcept
Create a tuple of lvalue or rvalue references to the arguments.
Definition tuple:2678
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition move.h:127
constexpr piecewise_construct_t piecewise_construct
Tag for piecewise construction of std::pair objects.
Definition stl_pair.h:82
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition move.h:51
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition move.h:70
_Tp * end(valarray< _Tp > &__va) noexcept
Return an iterator pointing to one past the last element of the valarray.
Definition valarray:1251
_Tp * begin(valarray< _Tp > &__va) noexcept
Return an iterator pointing to the first element of the valarray.
Definition valarray:1229
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
ISO C++ entities toplevel namespace is std.
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
constexpr auto cend(const _Container &__cont) noexcept(noexcept(std::end(__cont))) -> decltype(std::end(__cont))
Return an iterator pointing to one past the last element of the const container.
constexpr auto empty(const _Container &__cont) noexcept(noexcept(__cont.empty())) -> decltype(__cont.empty())
Return whether a container is empty.
constexpr auto size(const _Container &__cont) noexcept(noexcept(__cont.size())) -> decltype(__cont.size())
Return the size of a container.
constexpr auto cbegin(const _Container &__cont) noexcept(noexcept(std::begin(__cont))) -> decltype(std::begin(__cont))
Return an iterator pointing to the first element of the const container.
Struct holding two objects of arbitrary type.
Definition stl_pair.h:286
_T1 first
The first member.
Definition stl_pair.h:290
_T2 second
The second member.
Definition stl_pair.h:291